The 39-year-old will star alongside Waleed Aly and Peter Hellier for three or four nights a week.
It has been reported that the mother-of-three was offered a radio gig by Southern Cross Austereo, but declined after welcoming her third child Adelaide 11 months ago.
The Nine Network also denied that it approached Carrie to help revive the ailing Today Show.
“Nine has not approached, and does not intend to approach, Carrie Bickmore or her representatives about joining Nine as a host of the Today Show, nor in any other role,” said director of news and current affairs, Darren Wick.