Robert Downey's Birthday Brings out the A-List

Hollywood's A-list couples came out to play on Saturday night, April 4, to celebrate Robert Downey Jr.'s birthday at Bond St. in the Thompson Hotel located in Beverly Hills.

In a very rare joint public appearance, RDJ's Iron Man co-star Gwyneth Paltrow was accompanied by her hubby Chris Martin for the féte.

According to a source, they "arrived together looking very happy." Despite rampant rumors that the Oscar-winner and the Coldplay front man are having marital issues, the source said that on Saturday, "you could really tell they are content together."

Martin was not the only thing Gwyneth was digging.

"Gwyneth really liked the sushi," an onlooker tells OK! "She even stopped one of the servers carrying a tray to get more spicy tuna rolls."

But the winners of the night's PDA award were Reese Witherspoon, whose left hand was without a ring, and Jake Gyllenhaal. "They looked so in love, and were really affectionate the entire night," a source tells OK!

NEW PICS FROM THE SET OF IRON MAN 2:

Among the 75 guests were Sting and his wife Trudie Styler, Ben Stiller and wife Christine Taylor, Iron Man director Jon Favreau, and Sam Rockwell, who is co-starring with Robert in the currently filming sequel.