Britney Spears' friends are reportedly worried she is ''moving too fast'' with new boyfriend Sam Asghari.

The 35-year-old pop star met her new beau Sam, 22, on the set of her music video for her single 'Slumber Party' last year, and although the pair seem happy, Britney's pals are concerned she's been ''thrown off-balance'' by having a ''new guy in her life'' and is rushing into making the relationship more serious than it needs to be.

A source told HollywoodLife.com: ''Britney has been thrown off-balance by Sam, the hot new guy in her life. Her friends and family have been trying to warn her that she is moving too fast.

''Those close to Britney are warning her that Sam may not be the best match for a star of her calibre. They are urging Britney to slow down with Sam, even though Britney is way into him and friends fear she trusts him maybe way more than she should.''

The blonde beauty - who has sons Sean, 11, and Jayden, 10, with ex-husband Kevin Federline - first sparked rumours of a romance with the personal trainer in November when the pair were spotted having dinner together, and quickly became ''totally smitten''.

A source said previously: ''This is the longest Britney has ever been out of a serious relationship and she's made no secret of the fact that she's been desperately lonely. She's been quietly dating for the past year, but Sam is the first man she's met who has swept her off her feet and she's totally smitten.''

The 'Toxic' hitmaker's romance with Sam comes after she revealed she was tired of men playing ''mind games'', and really wants to settle down with a ''nice guy''.

She said: ''A lot of men are about games. It's just the mind game with guys, the calling back and texting, it's just too much, it's silly. Actually, I'm not looking for men right now, I'm really happy with myself. I'm not looking for anything, I'm fine with the way I am.

''I like someone that's just nice overall, just a nice guy really is groundbreaking in this world.''