Celebrities and members of the royal family run in similar circles.
Even famous people get starstruck sometimes.
Photos show royals meeting celebrities like Nicole Kidman, Taylor Swift, and Anna Wintour.
Queen Elizabeth and Anna Wintour sat next to each other at a runway show.
Queen Elizabeth and Wintour viewed Richard Quinn's runway show before presenting him with the inaugural Queen Elizabeth II Award for British Design at London Fashion Week in 2018.
Kate Middleton and Harry Styles shared a moment that Simon Cowell gleefully witnessed.
Kate Middleton met Harry Styles (then a member of One Direction) as Simon Cowell looked on at the end of The Royal Variety Performance at the London Palladium in 2014.
Cara Delevingne had a laugh with King Charles (then Prince of Wales) at a charity event.
Delevingne met Charles at a charity reception to save the Asian elephant from extinction in the wild at Clarence House in 2013.
Kanye West and P. Diddy joked around with the two young princes back in 2007.
Prince William, Kanye West, Prince Harry, and P. Diddy attended a reception after a concert in memory of Princess Diana at Wembley Stadium in 2007.
Reese Witherspoon was thrilled to meet Middleton at a 2011 reception in California.
Middleton met Witherspoon at a reception to mark the Launch of Tusk Trust's US Patron's Circle in Santa Barbara, California.
Jennifer Garner also beamed when she met the Princess of Wales (then the Duchess of Cambridge).
Middleton talked to Jennifer Garner at the 2011 BAFTA Brits To Watch Event in Los Angeles in 2011.
Tom Cruise charmed Prince Philip at Buckingham Palace in 2017.
Philip and Cruise met during a dinner to mark the 75th anniversary of the Outward Bound Trust at Buckingham Palace.
Prince William played it super cool when talking to Nicole Kidman at a BAFTA event in 2011.
William made Kidman's acquaintance at the 2011 BAFTA Brits To Watch event in Los Angeles.
Jennifer Lopez brought her mom along to meet William and Kate.
Lopez and her mother Guadalupe Lopez met the royal couple at the 2011 BAFTA Brits To Watch event.
LeBron James got so excited that he broke the no-touching-royals rule in 2014.
William and Kate posed with James backstage at a Cleveland Cavaliers vs. Brooklyn Nets game in 2014. People aren't supposed to touch royals unless the royals themselves initiate contact, but James isn't the first celebrity to accidentally break protocol.
Angelina Jolie was visibly moved when she received the insignia of an Honorary Dame from the Queen for her humanitarian work combating sexual violence in 2014.
Angelina Jolie was presented with the Insignia of an Honorary Dame Grand Cross of the Most Distinguished Order of St Michael and St George in the 1844 Room at Buckingham Palace.
Barclays Center erupted in applause when the Prince and Princess of Wales (then the Duke and Duchess of Cambridge) met Queen Bey and Jay-Z at a basketball game.
William spoke with Jay-Z while Kate chatted with Beyoncé during a Brooklyn Nets game in 2014.
William and Taylor Swift exchanged pleasantries at a charity gala in 2013.
Swift sang "Living On A Prayer" with William and Jon Bon Jovi at the Winter Whites Gala at Kensington Palace in 2013.