Show bosses are said to have approached the presenter after she left BBC Breakfast in March, following its move from London to Manchester.
A source told The Sun: "She is hugely popular with BBC viewers and is fit as a fiddle so we want her on the dancefloor."
Williams had previously danced for a Children in Need special of the programme in November.
She will reportedly be joined by Winter Olympics gold medal winner Amy Williams, who recently retired from skeleton racing.
The source added: "Amy is full of beans and is really fun to have around."
Britain's Got Talent winner Ashleigh Butler, Fern Britton and cricketer Michael Vaughan have also been tipped to star in the upcoming series later this year.