Robert Downey Jr. may not be a superhero in real life, but he sure knows how to make his wife feel special!
E! News has exclusively learned that the Iron Man star threw a star-studded bash for his wife Susan's 40th birthday, hosting a celebration at Cavallo Point near Sausalito, Calif. where guests, including Justin Theroux, Gwen Stefani, Gavin Rossdale, Gwyneth Paltrow, Jon Favreau and Reese Witherspoon, spent the entire weekend relaxing at a resort spa.
"It was a great weekend for Susan, and Robert went all out to make sure she knows how special she is," a source exclusively tells E! News of the getaway. "Around 50 of their closest friends came up for the weekend and stayed at the hotel in historic houses. It was a very relaxing weekend and there was a lot of time for people to catch up."
Guests spent the weekend enjoying the amenities at the resort, getting spa treatments, going on walks and celebrating Susan's birthday.
On Saturday night, there was a birthday party held in a ballroom of the hotel with dinner and dancing, and after the party there was a spectacular fireworks show over the water next to the Golden Gate Bridge. (How picturesque!)
"There were kids running around everywhere, and the whole weekend catered to families," the source says. "They had lot of kids' entertainment and the children were included in all of the events, even the nighttime birthday party. The whole group was very tight and very friendly. There was lots of hugging and reminiscing with old friends."
As for the A-list attendees?
"Justin Theroux attended the party without Jennifer Aniston," the insider adds. "He was tight with all of the guys especially Jason Bateman, Gavin Rossdale and Jon Favreau. He was in great spirits and seemed to know a lot of people there."
Paltrow, who has starred with RDJ in all three Iron Man flicks, stayed close to her costar and his wife, clearly enjoying their company.
"Gwyneth was very friendly with Robert and Susan," the source says. "They are very close after the movies and couldn't get enough of each other. They were always talking closely and putting their arms around each other."
"Reese did her own thing and visited with friends she knows in the area," the insider reveals. "She had her family with her and they had a lot of family time together hanging out."
On Sunday morning, partygoers were served brunch with food trucks and a coffee bar in the parking lot, and everyone picnicked outside and chatted together. Guests all sang happy birthday to Susan before packing up their bags and heading off to the airport.
"When it was time to go on Sunday, everyone talked about how much fun they had and that it was too short," the source says. "They wished it could have lasted longer."
Nice job, RDJ! And happy birthday, Susan!