Credit: AKM-GSI; George Pimentel/WireImage

Gwyneth Paltrow really is friends with everyone -- including ex-boyfriend Brad Pitt's famous ex-wife Jennifer Aniston! Along with rocker hubby Chris Martin, the GOOP founder, 41, was among the many A-list attendees at Aniston and fiance Justin Theroux's annual holiday and tree trimming party at their Bel Air home in on Sunday, Dec. 8. More pictures of unlikely celebrity besties.

Paltrow and the Coldplay singer, 36, were photographed driving themselves to the bash, with Martin behind the wheel and the Oscar winner clad in a fur coat and dark lipstick. Other guests at the fete -- where revelers decorated a giant Noble Fir -- included Courteney Cox, Robert Downey Jr and his wife Susan, Jason Bateman, Tobey Maguire and wife Jennifer Meyer, Isla Fisher, Will Arnett and Chelsea Handler.

Famous in part for her many, many famous pals, Paltrow has never spoken much about her friendship with Aniston, 44, but the pair have at least one thing in common: Pitt, 49. The Iron Man 3 actress and Pitt dated from 1994 to 1997, and were even briefly engaged. Pitt and Aniston, of course, were married from 2000 to 2005, with Pitt moving on with now-fiancee Angelina Jolie.

Now a father of six with Jolie, 38, the 12 Years a Slave actor has intimated that he wasn't his best self during his relationships with both Paltrow and Aniston.

"I spent the '90s trying to hide out, trying to duck the full celebrity cacophony. I started to get sick of myself sitting on a couch, holding a joint, hiding out. It started feeling pathetic," he told Parade in an infamous 2011 interview.

"I wasn't living an interesting life myself," he continued. "I think that my marriage had something to do with it. Trying to pretend the marriage was something that it wasn't."