N-Dubz are rumoured to be on the verge of splitting.

The 'Girls' group are said to have fallen out over singer Tulisa's appointment as a judge on UK TV show 'The X Factor', which rapper Dappy feels is taking her focus off the band, leading him to sign with a new management company to launch his solo career.

A source told The Sun newspaper: "Dappy is livid about the whole situation. Tulisa has a new passion now - and that's not what they got into the business for.

"He has thrown himself into his solo career because, as far as he is concerned, N-Dubz is all but over.

"The last album didn't do as well as he hoped and 'X Factor' has caused a lot of problems between them."

Dappy has previously talked of his plans to start a solo career and planned a single for September.

He said: "The first single is coming and it's called 'No Reg¬rets'. It's all about me as a person and explains why I've been so crazy and spontaneous."

Third group member, producer Fazer- long rumoured to be Tulisa's boyfriend - is stuck in the middle, although he has already started making plans to produce tracks for other people, with him rumoured to be writing music for Katy Perry's next album.

Tulisa is also rumoured to be planning a solo career off the back of her appearance on 'The X Factor'.

An official spokesperson for N-Dubz is confident that while they will pursue solo projects, the group will return, saying: "They have shows throughout 2011 and plans are in place for another single and album. The band are definitely not splitting up."