MK1 are "really tight" with 'X Factor' mentor Tulisa Contostavlos.

The duo Charlie and Sim admit they would not swap their own mentor Louis for the 'Young' singer, but are glad she has given them positive comments both on and off stage.

Charlie told BANG Showbiz: "We're really tight with Tulisa - we're her dark horse in the competition and she said we could follow in Little Mix's footsteps which is really nice to hear. We were a bit worried being an urban act on the show, because we're not perfect 'X Factor' material. But to have one of the judge's say that, it's a boost."

Sim added: "To begin with we were keen on having Tulisa. But over the past few weeks Louis, it's like, he understands, and we're grateful for his experience too. That's so paramount for us.

Tulisa previously said on the live show that the duo could not rival her band N-Dubz - with who she is reuniting - but Charlie claims she has always been happy to help them.

She added: "She's the kind of girl that if you need to talk to her about something, she's there. We've spoken to her about a couple of things, not that Louis couldn't answer that question but we'll be like, 'Tulisa, we've just seen you...' she's really helpful. Not so much with Gary and Nicole, but that's alright."