Lady Gaga and Mick Jagger perform onstage during the Rolling Stones final concert of their "50 and Counting Tour" in Newark, New Jersey, December 15, 2012 .

The Rolling Stones partied with Lady Gaga until 3am after their gig on Saturday night.

The veteran rockers - made up of Sir Mick Jagger, Ronnie Wood, Charlie Watts and Keith Richards - and the 'Born This Way' hitmaker enjoyed a “relaxed” affair at The Carlyle Hotel, New York City, with 150 others following their collaboration at the Prudential Center in Newark, New Jersey.

An insider told the New York Daily News newspaper: “The party went from around midnight to almost 3am. They really just hung out, relaxed and all chatted with each other.”

Earlier in the evening, Gaga performed a rendition of 'Gimme Shelter' with the 'Brown Sugar' hitmakers for their final '50 and Counting' show, which also saw them take to the stage with Bruce Springsteen and The Black Keys, to celebrate their 50th year of rock 'n' roll.

The group enjoyed another “laid-back” star-studded party at The Carlyle Hotel on Thursday night to celebrate their penultimate '50 and Counting' show earlier in the evening.

A source told the New York Post newspaper: “It was a pretty laid-back party. Charlie Watts left before midnight, but he's 71.”

Guests at the chilled out event included Mick's daughter Jade Jagger and his girlfriend L'Wren Scott, Ronnie Wood's fiancée Sally Humphreys, Keith's wife Patti Hansen and Foo Fighters rocker Dave Grohl.

The Rolling Stones performed a 22-song set at the gig, including their 1978 hit 'Respectable' with John Mayer, and their former bandmate Mick Taylor also made an appearance. - BANG Showbiz