(Cover) - EN Showbiz - Bradley Cooper and Zoe Saldana celebrated the New Year by "making out for 20 minutes".

The Hollywood pair have been dating for the last few months and decided to spend December 31 together. They attended a 40s themed party in Los Angeles and surprised guests with their flirtatious manner.

"They were making out for 20 minutes!" a source laughed to Us Weekly.

Bradley and Zoe were introduced last February when production began on their film The Words.

Although it may seem that they have only just started dating, In Touch reports that they have been quietly seen each other for a few months.

But they apparently didn't officially get together until Zoe, 33, ended her long-term relationship with her partner of 11 years Keith Britton.

"Bradley and Zoe hit it off instantly," a source from the set said. "You could tell that there was an attraction, but he waited until she split with Keith before he made a move."

The two play lovers in the upcoming film but Life & Style says that Zoe has now fallen for the hunky actor off screen.

"Bradley has exactly what Zoe likes in a guy," a source told the magazine. "He's handsome and doesn't take himself too seriously. Also Zoe loves to laugh, and Bradley's extremely funny." (C) Cover Media