A general rule of thumb is that you stay away from your friend's ex. But that doesn't seem to apply in Hollywood. E! Online has compiled a list of 10 celebrities that have dated their friends' exes. Interestingly, Taylor Swift's name comes up several times. Check it out:
  • Katy Perry/John Mayer/Taylor Swift: The notorious player hooked up with Swift when she was just 19-years-old. A few years later, Mayer entered a high-profile relationship with Perry, who is (was?) pals with T-Swift. 
  • Heather Locklear/Richie Sambora/Denise Richards: Locklear and Richards were great friends -- until Locklear's marriage to Sambora went downhill and he started dating Richards.
  • Taylor Swift/Joe Jonas/Demi Lovato/Ashley Greene: This one is a little more complicated: Swift, who is friends with both Lovato and Greene, was the first to date the Jonas brother. Shortly after, Joe dated Demi, and then he dated Greene, who he allegedly lost his virginity to.
  • Lindsay Lohan/Aaron Carter/Hilary Duff: Duff and Carter were an item back in their teens. But she dumped him when he hooked up with her friend Lindsay Lohan.
  • Drew Barrymore/Fabrizio Moretti/Kristen Wiig: There's surprisingly no drama here. In an interview with Allure back in 2012, Barrymore explained about her friend Wiig's relationship with her Strokes drummer ex: "It all seems so wacky and incestuous, but that's kind of how life works. It seems fitting that they would find each other. I was like, 'Right, of course, that makes perfect sense.'"
  • Taylor Swift/Taylor Lautner/Selena Gomez: The two singers are still good friends, but another thing they have in common is that they dated the Twilight star. 
  • Taylor Swift/Harry Styles/Cara Delevingne: The One Direction cutie had a whirlwind romance with Swift, after which he started hanging out with Delevingne. Interestingly, Swift and the British supermodel became close after that. Perhaps they had some interesting stories to swap?
  • Elizabeth Taylor/Eddie Fisher/Debbie Reynolds: This love triangle is one of Hollywood's most scandalous stories. After her third husband died in a plane crash, Taylor cried on the shoulder of her good friend Debbie Reynolds' husband, Eddie Fisher. He ended up leaving Reynolds to be with Elizabeth. Oddly enough, Reynolds and Taylor ended up rekindling their friendship years later. Sisters before misters!
  • Miley Cyrus/Nick Jonas/Selena Gomez: Cyrus and Gomez were great friends -- until Jonas came between them. Gomez started dating the musician after he and Cyrus called it quits. Things have been passive aggressive between the two pop stars ever since. 
  • Kate Hudson/Alex Rodriguez/Cameron Diaz: According to reports, the two blondes had a falling out after Diaz pursued the baseball player shortly after Hudson's fling with him fizzled.