Kat Dennings is reportedly dating Josh Groban.

The '2 Broke Girls' star, 28, has sparked rumours she's romancing the 'Brave' singer, 33, after they were spotted acting like a couple at the Carousel of Hope Ball in Beverly Hills, California, on Saturday (11.10.14).

An eyewitness told E! News: ''They were so cute together! They were adorable on the carpet.

''She was whispering in his ear a lot and they seemed really happy.''

Prior to dating Josh, the brunette beauty was in a relationship with Nick Zano, who starred in the American sitcom as Johnny in season one and two, while Josh has previously dated January Jones and also been romantically linked to Katy Perry in the past.

The hunk previously admitted he quite enjoyed being single but sometimes found life a little bit lonely without a lover by his side.

He said last year: ''I am single and I do enjoy it. I enjoy being in a relationship too, though.

''I like the saying, 'A good relationship is a friendship on fire.' It's nice to have a companion - especially when you're a solo artist, as it can be very lonely.''