Because in Hollywood, when celebrities run into their exes, there's always a camera or two around. Below, a round-up of celebrity ex-lover reunions that made everyone around them feel trés awkward.
Jennifer Lopez, Casper Smart and Diddy (2013): Diddy looked bemused as he reached out for a handshake with ex-girlfriend Jennifer Lopez's new beau, 25-year-old Casper Smart. Diddy and Jenny from the block dated over a decade earlier, from 1999 to 2001.
Demi Moore, Ashton Kutcher and Bruce Willis (2003): In the mid-2000s, Demi Moore, then-boyfriend/future husband Ashton Kutcher and ex-husband Bruce Willis famously got along, making us think that women really could have it all. The trio even vacationed together at Willis' home in Turks and Caicos, a trip that produced these photos shot by Annie Leibovitz for Vanity Fair.
Simon Cowell, Sinitta and Jackie St. Clair (2010): The "X Factor" creator and notorious bachelor posed not with one, but two ex-girlfriends on the red carpet at the 2010 National Television Awards in London. Both also continue to be favorite companions aboard the television personality's yacht.
Kimora Lee Simmons, Russell Simmons and Djimon Hounsou (2011): The hip-hop producer and model ex-wife remain close, which helps explain this group family portrait with Kimora's then-boyfriend Djimon Hounsou.
Jennifer Lopez, Casper Smart and Marc Anthony (2013): J.Lo strikes again. After divorcing her husband of seven years in 2011, Jennifer Lopez quickly moved on to backup dancer Smart. No hard feelings though, evidently: the exes posed with their new partners at the birthday party for Anthony's 12-year-old son.
Reese Witherspoon, Ryan Phillippe and Jim Toth (2013): The Oscar-winning actress and ex-husband appeared civil while watching their son Deacon's soccer game in May. Witherspoon's current husband, Jim Toth, accompanied her while an unnamed female sat to Phillippe's right.
Britney Spears, Kevin Federline (2013): Nope, not awkward at all: Britney Spears looked just like any other mom at her sons' soccer match, despite the presence of notorious ex-husband Kevin Federline and his new girlfriend (not pictured).