It's been quite a day for Kate Middleton! Kate Middleton and Prince William attended the Queen's birthday celebration earlier today, and this afternoon the Duchess of Cambridge changed her dress, but kept her fascinator, to join her sister Pippa at their friend's wedding. Kate and Pippa were both in black pumps and summery dresses to watch jockey Sam Waley Cohen and his bride Bella Ballin tie the knot in Berkshire, UK. Princess Beatrice and her boyfriend Dave Clark also attended the ceremony. The groom reportedly played a crucial role in the relationship of Kate and Prince William, since Sam is credited with bringing the couple back together when they briefly split. Sam and Bella have been longtime friends of Kate and Will and were on the guest list for the royal wedding in April. Kate made her first official royal appearances this week as well, stepping out in a stunning Jenny Packham gown for the ARK dinner on Thursday.

The Duchess of Cambridge, Kate Middleton, shared a carriage with Prince Harry, her mother-in-law Camilla Parker-Bowles, and Prince Wiliam's uncle Prince Andrew this morning at the Trooping the Colour procession in London. The annual ceremony is held to recognize the birthday of the sovereign, though Queen Elizabeth actually turned 85 on April 21. The royals tend to celebrate the Queen's big day in the Summer, however, as the weather is better for outdoor events. Her husband, Prince Philip, actually just celebrated a milestone — Philip's 90th birthday was yesterday! He received a new title for the occasion. Prince Philip, known as the Duke of Edinburgh, is now also the Lord High Admiral of the navy, and is planning to begin scaling back his official workload. This was William's first time riding in the parade, and he was able to wear the distinctive bearskin hat while riding next to his father Charles. William wore the Irish Guards uniform, which he donned during his April 29 wedding to Kate, for the first time since their nuptials. The pomp wrapped up with William's family reuniting on the balcony of Buckingham Palace as well. William and his wife have had a busy week of social obligations, after Kate dazzled in Jenny Packham at Thursday's ARK dinner.

Lily Allen married fiancé Sam Cooper in a picturesque wedding ceremony at James the Great Church in Gloucestershire, England, today. The singer, who is also pregnant, wore a stunning gown by French designer Delphine Manivet for her big day, and she had a huge smile on her face as she and her new husband stepped out after their ceremony. The intimate event was attended by under 100 people, including many of their friends. Sam and Lily have been together since 2009 and he popped the question over the holidays. Lily Allen rehearsed her wedding on Friday before actually walking down the aisle this afternoon. Congrats to the newlyweds!

It was a week full of romance and raucous awards shows for some of our favorite stars! Robert Pattinson and Kristen Stewart cozied up at the MTV Movie Awards, while Jennifer Aniston and Justin Theroux saved their PDA for the afterparty. The Twilight stars swept Sunday's show, but Jennifer and Ben Affleck each took home honors at Saturday's Guys Choice Awards. Kate Middleton and Prince William, meanwhile, were across the pond making jaws drop with their first official social engagement as a married couple. Check out all of these pictures, and even more memorable photos, in the gallery!

Nicole Kidman was decked out in head-to-toe cream as she arrived on a flight at LAX Thursday night. The actress is on the go after making an appearance at the CMT Music Awards in Nashville on Wednesday. She was there to support husband Keith Urban since he was nominated for multiple honors including male video of the year. Keith didn't walk away with any wins, but he has his upcoming tour to keep his mind off any disappointment. The Get Closer Tour opens next week and it'll take him across the country and to Canada, but Keith has his schedule planned so that he never spends more than a few days away from his family. The Kidman-Urbans have a lot to juggle between Keith's music and Nicole's acting career, though the timing of his show works out since she just wrapped her HBO film Hemingway and Gellhorn.

Reese Witherspoon was spotted running errands in Beverly Hills on Friday. She was back to her usual casual look after getting dressed up for the MTV Movie Awards last weekend. The actress was honored with the MTV Generation Award and her Water For Elephants costar, Robert Pattinson, along with Patrick Dempsey, had the pleasure of presenting Reese with the statue. Rob's speech was a little loopy, though Reese pulled things together with her empowering acceptance when she took the stage. Reese will have the chance to continue her movie making success with the addition of her latest project Who Invited Her?, a comedy about a woman who tags along at a bachelor party.

Katie Holmes started her morning in Beverly Hills yesterday with a stop at one of her favorite bakeries, Le Pain Quotidien. Suri missed out on the trip, but she and Katie are well-known fans of their famous croissants. Katie's all about her LA eateries this week and was also spotted lunching with friends at Urth Cafe. She's been taking care of business and prepping for the August release of her horror flick — check out the latest terrifying trailer for Don't Be Afraid of the Dark. Meanwhile, Tom Cruise is taking a break from Rock of Ages to spend time with his girls, and even supported his pals J.J. Abrams and Steven Spielberg Wednesday at the premiere of Super 8.