"They looked so close, they almost seem like a couple,” the source told Us Weekly of Cooper and Gaga's interaction at the party. Cooper's long-time girlfriend, Russian model Irina Shayk, with whom he shares a daughter, 23-month-old Lea De Seine, was not in attendance at the party. Lady Gaga's recent ex, Christian Carino, was however.
"Christian Carino walked into the party…said hi to Gaga at one point," the party source said. "But it was brief and then he went to another room."
Gaga and Carino's split is still fresh; news that the former couple had decided to call off their engagement broke last week.
WATCH: Lady Gaga And Bradley Cooper Are Confirmed To Perform 'Shallow' At The Oscars.