Matthew Perry & Lizzy Caplan Join List of Hollywood’s Random Couples (PHOTOS)

Who knew Chandler Bing and Janis Ian would make such an adorable couple?!

Friends star Matthew Perry, 42 and Mean Girls actress Lizzy Caplan, 29 (who have been quietly seeing each other for quiet some time now) made a rare public appearance as they joined the slew of stars taking in tennis matches at the US Open in NYC on Thursday. The two looked like they were having a great time as they laughed and smiled during the entire game.

These two aren’t the only stars whose relationship have people scratching their heads.

From Alec Baldwin and his much younger yoga instructor girlfriend to Twilight star Nikki Reed and American Idol’s Paul McDonald’s whirlwind romance, there are plenty of surprise couples that make it work.

Although some have since broken up (like Christina Aguilera and her ex-hubby Jordan Bratman), we were able to put together this list of some of the most random celebrity couples.

Take a gander through the gallery and let us know on Twitter or Facebook — which do you think is the MOST random?