The producer - real name Richard Rawson - has been appointed by Simon Cowell to work with the winning act.
"I'll be producing for the X Factor winner, it's been decided," he told The Sun. "This isn't just a hook-up with [girlfriend] Tulisa [Contostavlos], I'm going to work with whichever act wins.
"I've been talking to SyCo about working on a few different things for them."
Fazer added: "We really want to give a new flavour to the X Factor acts. It's going to suit me. I have rock influences, hip-hop, pop, whatever.
"I have produced Dappy's new track and songs for Tulisa too. I'm hoping for the Christmas numbers one and two."
It was previously reported that X Factor judge Gary Barlow will be writing the song for this year's winner.
Earlier this year, it was revealed that Fazer has written a song for Katy Perry, which he hopes will be used as one of her future singles.
Watch the music video for N-Dubz' 'Girls' below: