updated 05/12/2014 AT 7:00 AM ET
•originally published 05/12/2014 AT 8:15 AM ET
The couple, who got engaged last month, partied with pals at Cafe Habana, which is owned by Clooney’s friend and business partner Rande Gerber.
Guests, including Gerber and his wife Cindy Crawford, as well as U2’s Bono and The Edge, gathered on the restaurant’s patio, according to a source, who added that several of the guests performed karaoke.
The group toasted the couple with tequila and also sipped wine.
“After the toast, George and his fiancée were all over each other,” a source says. “Lots of hugging.”
Alamuddin was showing off her emerald-cut diamond engagement ring (estimated at more than 7 carats and which Clooney helped design) at the party, which ended early in the evening.
According to the source, Clooney, 53, and Alamuddin, 36, left in a limo, toting gifts and flowers.