The Tonight's the Night presenter signed up as a contestant on the dance show's Christmas special last week, revealing that he was a huge fan of the BBC reality series.
However, according to the Daily Express, the Torchwood actor is the new favourite to replace Forsyth when the showbiz veteran eventually retires from the programme.
Despite increased viewing figures for the new series of Strictly, Forsyth is expected to withdraw from the show in the next couple of years. During the current run, Claudia Winkleman has replaced him on the Sunday night results show to reduce the 82-year-old's workload.
Anton Du Beke and Vernon Kay have previously been suggested as replacements for Forsyth on the entertainment programme.