Summer typically means a lot of time spent outdoors, and there's no one who knows more about what's it like to work up a sweat in the sun than athletes. To celebrate the official start of Summer at the end of this week, we're looking at a few of the best beach and pool moments from our favorite sports stars — you don't have to be an avid sports fan to like these celebrities! Click through to see Serena Williams, David Beckham, Ryan Lochte, and more athletes let loose when they're not working on their game.

Now that Kate Middleton has officially begun her maternity leave, she can focus her time on relaxing with Prince William and preparing for her baby's arrival. With that in mind, we're taking a look at the royal family's best off-duty moments — from slipping into bikinis on exotic vacations to hitting the polo field with their relatives and pals. Click through to see how Kate, William, Prince Harry, and the rest of the royals let loose when they aren't making official appearances.

Kim Kardashian and Kanye West are still picking out a name for their daughter, whom they welcomed on Saturday, and it seems unlikely that she'll share her moniker with any other celebrity babies. Other stars have given their kids similar names, though, like JoAnna Garcia and Nick Swisher, whose daughter, Emme, short for Emerson, has the same name that Jennifer Lopez and Marc Anthony gave their daughter. Angelina Jolie, Gisele Bündchen, and many more have given their children the same names as some of their Hollywood peers. Click through to see which stars are on the same wavelength when it comes to baby names!

Yesterday's LA premiere for Monsters University was full of more famous tots than a Hollywood playground. Gwen Stefani and Gavin Rossdale walked the blue carpet with their sons, Kingston and Zuma, while Alessandra Ambrosio modeled alongside her adorable daughter, Anja. Melissa Joan Hart also dropped by the bash with her son, Tucker, whom she carried into the premiere. The kid-friendly bash also drew stars from the film like Billy Crystal, Sean Hayes, and Charlie Day, who told us earlier this week that he is happy to be doing a project that "won't embarrass his parents." Check out our interview with Charlie Day, and be sure to watch our review of Monsters University to see if it's worth checking out this weekend.

Beyoncé showed her support for Jay-Z when she attended the 10th anniversary party for his 40/40 Club in NYC last night. She wore a white Roberto Cavalli gown as she sipped on Champagne and mingled with guests like T.I., his wife, Tiny, and Kylie Minogue, who put her legs on display in an Anthony Vaccarello minidress. Beyoncé showed her support for another friend, Kanye West, yesterday when she publicly congratulated him and Kim Kardashian on the birth of their first child. She was by Kanye's side last week when she and Jay-Z attended a listening party for Yeezus in NYC last Monday. Kanye had been touring around the country to host listening parties for his new record but had to pull out of his bash last Friday in LA when Kim reportedly told him that she wasn't feeling well and was checking into the hospital.

The LA Film Festival kicked off last Thursday, and stars have already flocked to the event to promote their newest projects. Yesterday, Octavia Spencer stepped out for the Fruitvale Station premiere, while Shailene Woodley attended her The Spectacular Now debut. On Saturday, Rooney Mara met up with Casey Affleck to show support for their flick, Ain't Them Bodies Saints, while Alessandra Ambrosio took her daughter, Anja, to the premiere of My Little Pony: Equestria Girls. Click through to see all the stars at the LA Film Festival — so far!

Katy Perry got personal about her relationships with Russell Brand and John Mayer in the July issue of Vogue, which hits newsstands on June 25. She donned sultry dresses to pose for famed photographer Annie Leibovitz for her photo spread and cover, but she revealed that her romantic life isn't quite as picture perfect as it would seem. Katy admits that her ex-husband, Russell Brand, told her he was seeking a divorce via text message, and also reveals that she is still in love with John Mayer. Read on for more from Katy Perry in Vogue.

• On her divorce from Russell Brand: "Let's just say I haven't heard from him since he texted me saying he was divorcing me December 31, 2011."
• On what caused their breakup: "I felt a lot of responsibility for it ending, but then I found out the real truth, which I can't necessarily disclose because I keep it locked in my safe for a rainy day. I let go and I was like: This isn't because of me; this is beyond me. So I have moved on from that."
• On her on-again, off-again relationship with John Mayer: "I was madly in love with him. I still am madly in love with him. . . . Beautiful mind, tortured soul."

Man of Steel won the box office over the weekend with over $113 million and the biggest June opening to date. Meanwhile, the film's big stars are traveling around the world for further promotions. Henry Cavill, Russell Crowe, and director Zack Snyder walked the red carpet in Madrid today for another premiere, but leading lady Amy Adams did not attend the latest Superman showcasing. Amy did take in a big bear hug from Russell on Saturday, though, when they attended a photocall at the Taormina Film Fest in Taormina, Italy. They were joined by Henry as the group posed for photos against the idyllic countryside.

The three actors have been hard at work promoting their film, including last week's NYC premiere followed by a London showing on Wednesday as well. While in England, the cast battled with the rain, which nearly soaked a Valentino-clad Amy. Luckily, an assistant covered her up with an umbrella, which she giggled about while taking photos. Before the cast headed over to Italy, they taped an interview for The Graham Norton Show, which aired in the UK on Friday.

Famous people celebrated Father's Day the same way millions of regular folks honored the holiday this year — by sharing cute vintage photos of themselves with their dads on social media! Click through to see the adorable snaps, including Taylor Swift playing with her dad, Candice Swanepoel getting in a cuddle with her father, and Sarah Hyland getting her hair done with her bearded papa.

Matt Lanter married Angela Stacy in Malibu on Friday with family and friends watching. Angela wore an ivory gown with a full skirt and a strapless sweetheart neckline and kept her hair down in loose waves. She topped her look off with a long veil and shared a snap of the ensemble on her Twitter account. Matt and Angela held their reception at Calamigos Ranch, where guests got a chance to pose on a personalized red carpet with a group of robots. Attendees included Miley Cyrus's ex-boyfriend Justin Gaston, who served as a groomsman for Matt's big day, and reportedly also played guitar during the ceremony. On Saturday, after the bash, Matt tweeted out a sweet message and a photo from his room at the Malibu Beach Inn writing, "Woke up this morning with an ocean view and a new bride. Blessed."

The stars stepped out with their dads and their little ones to celebrate Father's Day yesterday. Channing Tatum shared the first photo of his daughter, Everly Tatum, Dean McDermott floated in the pool with his little one, and LeAnn Rimes and Eddie Cibrian celebrated his birthday and dad's day. Meanwhile, Kendall Jenner and Kylie Jenner hung out with their dad, Bruce Jenner, while their half-sister Kim Kardashian recuperated in a hospital with brand-new dad Kanye West. Click through to see those celebrities and many more, and don't forget to check out the vintage Father's Day photos that the stars have been sharing!

Taylor Swift wore a curve-hugging Hervé Léger dress when she attended the 2013 MuchMusic Video Awards in Toronto last night. She was at the event to pick up the award for favorite international artist of the year and mingle with Canadian stars. Other celebrity attendees included an Amen-clad Lucy Hale, Naya Rivera and her boyfriend, Big Sean, Drake, and Avril Lavigne, who was joined on the red carpet by Chad Kroeger. Avril had a big night at the award show, as she scooped up the award for international video of the year by a Canadian for "Here's to Never Growing Up" and performed for a crowd of music fans.

It's been a big week for Taylor, who was honored with the celebrity fragrance of the year award at the Fragrance Foundation Awards in NYC last Wednesday. Don't miss our interview with Taylor Swift from last week's award show, where she talked about expanding her growing empire.

Prince William and Prince Harry took part in a friendly competition when they played against each other in a charity game at the International Audi Polo Match in Tetbury, England, today. The match fell on the same day as the Cartier Queen's Cup finals, which were attended by Queen Elizabeth II and Princess Beatrice. The royal brothers' game came just 24 hours after they donned their dress uniforms to attend the Trooping the Colour parade in London on Saturday. They were joined by the entire royal family (minus Prince Philip, who is recovering in a hospital) for the occasion, which serves as a belated public birthday celebration for the queen. Kate Middleton made her final public appearance at the event, where she wore a pink Alexander McQueen coat, fueling speculation that she is pregnant with a baby girl.

Serena Williams donned a bikini when she hit the beach on Saturday with a group of friends in Miami. She is fresh off her win at the French Open last week, having defeated Maria Sharapova in the finals in Paris. Serena shared her trip to the beach on her Twitter account, tweeting that she was at the Soho House in Miami and posting playful shots of herself lying out on a chaise. She is getting in her vacation time before she heads back to the court in London for the 2013 Wimbledon Championships on June 24. Serena is currently the reigning champion at Wimbledon, having won the Women's Singles and the Women's Doubles alongside sister Venus Williams last year. If looking at Serena's toned figure is getting you in the mood to work out, be sure to check out our guide on how to get Serena Williams's abs.

Reese Witherspoon accompanied Ava and Deacon to LAX yesterday where the group caught a flight out of LA. The family was joined by two other young tots as they made their way through the airport right before Father's Day. Notably absent were Jim Toth and Reese's son Tennessee, which suggests that Ava and Deacon may have been making a journey to meet up with their dad, Ryan Phillippe, who spent the weekend in Hawaii to attend the Maui Film Festival. While promoting his new project, Isolated, at the event, Ryan talked about how he and Reese aren't going to push their kids into show business and instead make sure that they finish their educations. He said, "I don't mean to dismiss or demean our industry but I'd like to see them do something a little more meaningful or important [than enter show business]. If I had the education and what they have offered to them as kids, I may have gone a different way." Ryan skipped college to pursue a career straight out of high school while Reese dropped out of Stanford after one year of schooling to jump into acting.

Since starting out 2013 with her pregnancy news, Kim Kardashian has taken her growing baby bump on a worldwide tour. She's made stops in Greece, Texas, Vegas, Miami, and Brazil, just to name a few. Many of her travels have been work-related, but her jet-setting also included romantic getaways with boyfriend Kanye West, who splits much of his time between Paris and NYC. Along the way, Kim hasn't been shy about sharing details from this exciting time in her life, talking candidly about her pregnancy over the past few months. You won't believe all the places she's been during her whirlwind of a pregnancy — click through to see the destinations Kim conquered before she gave birth to a baby girl!

— Additional reporting by Meg Rooney