So this is the reason they say opposites attract.
Everyone has that one ex who causes you to think, Ugh, why did I ever date him? And celebrities are no exception.
It's one thing to be embarrassed about a past relationship. But when you're in Hollywood, it's a yoyo of who's dated who. Can you say incestuous?
But just like us, stars aren't immune to making mistakes in the dating department. And thanks to them, we get to gossip about every one-night stand, quick fling or engagement that shouldn't have happened.
Take a celeb couple who hooked up in 2001 despite a seven year age difference (she was older!). Or two A-listers who were once engaged, oh, 20 years ago. Can you guess who?
Amanda Seyfried & Ryan Phillippe
Hindsight is 20/20, and it certainly was for Amanda Seyfried when she talked about her split with Ryan Phillippe, who's 11-years her senior. "You know when two people shouldn't be together from the get-go? That's why (we split)," Amanda said, post-breakup. Ouch. The seven-month relationship started as a fling when the two met at Kate Hudson's Halloween party and eventually left together. But when the sizzle fizzled, these two called it quits.
Natalie Portman & Moby
Talk about an odd couple! In a 2008 interview, musician Moby revealed he had a fling with every nerd's dream girl, Natalie Portman. "I guess in some people's eyes, [nerds] might be mildly sexy—and, as a nerd, I'm certainly happy to enjoy some of the effect of that. But as far as the very brief affair that I had with Natalie, it's made me a target of a lot of nerd wrath. You don't date Luke Skywalker's mom and not have them hate your guts."
Mickey Rourke & Evan Rachel Wood
Cast as father and daughter in the 2008 film The Wrestler, costars Mickey Rourke, 60, and Evan Rachel Wood, 25, took their relationship off-screen in 2009. Spies spotted the two actors lip-locking at a SAG after-party. According to eyewitnesses, Mickey grabbed Evan in the outside area of the Four Seasons Hotel in LA and planted a smooch on her. At the time, Evan had just called things off with Marilyn Manson. After the news of her new fling hit the web, she was quick to clarify that they were just friends. "Spread the word—I'm not dating Mickey Rourke," she said. We guess she just doesn't kiss and tell!
Matthew Morrison & Kristen Bell
These two TV stars had a romance that goes back to the dorm rooms. "I actually went to college with Matty Morrison," Kristen revealed in 2010. "We actually dated very briefly." If she wasn't so totally happy with fiance and baby daddy Dax Shepard, we totally would have loved to see these two together!
Kim Kardashian & Nick Cannon
Kim Kardashian-Cannon? It almost happened! After her split from Ray J, Kardashian rebounded with Nick Cannon. The couple split in 2007 after the release of her sex tape. "We talked about this tape, and she told me there was no tape," Cannon confessed. "If she might have been honest with me I might have tried to hold her down and be like, 'That was before me,' because she is a great girl. She's actually one of the nicest people you'll ever meet. But the fact that she lied and told me that there was no tape?" It was a deal-breaker for Cannon.
Kelly Preston & Charlie Sheen
Kelly Preston's happily married to John Travolta, but her dating history is filled with bad boys and bachelors! In 1988, she dated (and lived with!) George Clooney. The two even had a pet pig together—he kept Max after the split. But her most surprising ex is Charlie Sheen, and the two were briefly engaged in 1990. But they reportedly broke up because he, um, accidentally shot her in the arm. She set the record straight on the incident, explaining Sheen had a gun in the pocket of his pants. When it fell out, it accidentally discharged and injured her.
Justin Timberlake & Fergie
Fergie Timberlake does have a nice ring to it. But this couple-dom didn't have the stamina to last. The unlikely duo hooked up in 2001 when Fergie was known as one-third of girl group Wild Orchid and JT was fronting a little-known band named *NSYNC. "It wasn't a long-term serious relationship," Fergie confessed. "He was 16 and I was 23. It was before he got real heavy with Britney." We're guessing they were both saying, "Where is the Love?" before it was a hit collaboration.
Christina Applegate & Brad Pitt
Christina Applegate has one claim to fame not many women have: breaking Brad Pitt's heart! In 1988, the not-an-A-Lister-yet actor dated Christina, who was well-known for her role on Married ... With Children. "We were just part of this group of people that hung out and we decided to sort of cross the friend line," she revealed. "We went to the MTV Awards and I ditched him! I left with somebody else." We can say she's not the only one with a wandering eye.
Bruno Mars & Rita Ora
Before Rita broke Rob Kardashian's heart, she was head-over-heels in love with Bruno Mars. "It was love at first sight, such a great experience," she confesses. "We met in 2009. I was 18 and starting out at Roc Nation. Bruno was unknown back then, too. He was a struggling songwriter hired to write songs for me. I thought, 'Wow, that's just the world's greatest guy!''' And though it ended in 2011, the two still care for each other. "Our time together was wonderful. But once we got famous, work got in the way. We ended it last year. But we remained close. And when we were together, we were so happy." Now, let's play detective and figure out which songs he wrote about Rita!
Rihanna & Ashton Kutcher
Wham-bam, thank you ma'am? In 2012, Rihanna was seen visiting Ashton Kutcher's for-sale home during the wee hours on March 20 ... reportedly for a one-night stand. Sources said she arrived around midnight and left at 4 a.m. And apparently this wasn't the only time the two got cozy. "The flirting began as soon as Rihanna and Ashton met and swapped numbers. That moved onto texts and arranging to meet. They snuck off to a Santa Monica hotel...," a source said, at the time. "They are two single people having a fling, so thought it would be best to meet in secret. Rihanna has told friends he's funny and cute. Both of them love a good time and think they're too busy for anything serious just yet." Both have since moved on; Rihanna seems to be involved with on again off again boyfriend Drake and Ashton is welcoming a baby with his That '70s Show costar and fiancée Mila Kunis.