Reese Witherspoon, Cameron Diaz, Gwyneth Paltrow Have Girls Night Out -- With George Clooney!

Credit: Jason Merritt/Getty Images; D Dipasupil/FilmMagic; Jeff Vespa/WireImage

Blondes definitely have more fun -- especially en masse!

Reese Witherspoon, Cameron Diaz and Gwyneth Paltrow hit members-only club Soho House in West Hollywood Saturday night for a night of gossip and cocktails.

Witherspoon, 35, her hubby Jim Toth grabbed a table with fellow Oscar winner Paltrow, 39, Diaz, 39, and another male pal.

"The girls were all having such a good time together," a witness tells Us Weekly. "They were getting on really well and just laughing and conversing and enjoying one another's company. They were having a lot of fun!"

The super-trio weren't the only A-listers at Soho House that night, either. Just a couple tables away was George Clooney, hanging with friends but without love Stacy Keibler.

"There were occasional joint conversations between the two tables," explains the observer.