But, the "We Can't Stop" crooner and her hottie Hunger Games beau aren't the only celebs who have called it quits before they said "I Do."
Check out five other celebrities who called off their engagements:
Britney Spears: It looked like Britney and her former agent Jason Trawick were soon headed for matrimonial bliss, but the longtime couple ended their engagement in January--about a year after Jason popped the question on his 40th birthday in December 2011. "Jason and I have decided to call off our engagement," the "Work B-tch" crooner said in a statement, according to People. "I'll always adore him and we will remain great friends." The pop superstar and her former agent started dating in 2009.
Kelly Osbourne: The Fashion Police host and Luke Worrall called it quits back in 2010 amid reports her model beau had cheated on her, according to the Daily Mail. The couple began dating in May 2008 and announced their engagement less than a year later in March 2009. Kelly has since moved on and is now set to tie the knot with Matthew Mosshart, who popped the question during their vacation to Anguilla in July.
Joe Manganiello: The hunky True Blood star parted ways with his fiancé Audra Marie less than a year after he popped the question to her in October 2010 during their vacation in Italy. Following the 2011 split, Joe moved on to his now-girlfriend model Bridget Peters.
Zoe Saldana: The Star Trek star and her longtime beau, entrepreneur Keith Britton, got engaged in June 2010, and announced that they had called it off in November 2011. The couple's split came as somewhat of a shock, considering they had been dating for about 11 years. Following the split, Zoe said told InStyle UK she, "still believed in love," and it showed. She reportedly tied the knot in a secret ceremony to Italian artist Marco Perego this summer.
Kaley Cuoco: After announcing her engagement in October 2011, the Big Bang Theory star and her addiction specialist fiancé Josh Reznick called it quits in early 2012. When Entertainment Tonight asked Kaley whether her costar Kunal Nayyar's wedding gave her any ideas at the time, she said, "I'm not engaged anymore, anymore, so no...but in general, yes. For my future wedding, yes!"
Gallery | Celeb Couples: Which Lovebirds Will Last Longest?