Justin Theroux entertained guests with a "hilarious" rendition of pop hit Call Me Maybe at a post-Emmy Awards bash.

The actor was seen enjoying Jimmy Kimmel's party at a private members' club in West Hollywood after the ceremony, alongside The Office star John Krasinski.

The pair were spotted "dancing and singing" throughout the night.

"[They] were in a circle jumping up and down singing the end of [Carly Rae Jepsen's No. 1 smash single] Call Me Maybe. It was hilarious!" a source laughed to US Weekly.

"Justin was having a blast. After he had his Call Me Maybe dance party, he hopped behind the deejay booth with Samantha Ronson and she gave him a tutorial!"

Justin and John were enjoying the celebrations without their respective partners Jennifer Aniston and Emily Blunt.

The party attracted a wealth of A-listers though, including Robert Pattinson, Sofia Vergara, Chord Overstreet, Julie Bowen and Ashley Judd.

John reportedly congratulated Julie on her Emmy Award win with a "huge hug".

"He told her, 'You're killing it. Keep doing what you're doing. You deserve it and I'm so proud of you," an onlooker revealed.