Adam Levine enjoys 'casual' romance

Adam Levine's romance with Nina Agdal is a "new, casual thing".

It was reported earlier this week that the Maroon 5 frontman and Sports Illustrated model were dating, however, sources are now playing down the seriousness of the pair's relationship.

Adam - who split from girlfriend Behati Prinsloo in March - is keeping the romance with Nina, 21, low-key.

"It's very casual with Nina, actually," a source told People, adding that the pair "aren't taking things full-speed ahead."

"They're just getting to know each other. Unlike [Adam's exes] Behati and Anne [Vyalitsyna], where he was serious with them, this just seems to be a new, casual thing."

Despite Adam and Nina being in the early stages of their relationship, the beauty was spotted at a taping of The Voice US in Los Angeles on Monday.

"[Nina's] hair was up in a bun and she wore a low-cut, white sleeveless top and dark jeans," an audience member revealed.

"She was watching the show on a monitor with others backstage."

Adam, 34, is famed for romancing a string of stunning stars. He most recently split from Victoria's Secret Angel Behati and had previously dated Anne V.

The hunk has also been linked to Paris Hilton and Lindsay Lohan in the past.

Adam played down his lothario status in an interview earlier this year, insisting he wasn't always so popular with the opposite sex.

"I never had any issues there. But I wasn't a stud, the guy that was getting all the girls. I did OK," he said.