Talk about your star-studded parties.
Then again, this is George Clooney we're talking about here, who, along with fiancée Amal Alamuddin, celebrated their engagement with several famous friends at Cafe Habana in Malibu, Calif., on Sunday.
A source told E! News the low-key celebration was well underway around 7 p.m., noting that the restaurant was very busy because of the Mother's Day crowd.
"People got a show they didn't expect and other [restaurant patrons] said it was the best Mother's Day ever," one eyewitness exclusively shared with E! News.