Johnny Ball will be swapping numbers for rhumbas to become the oldest contestant to star in Strictly Come Dancing.
The 74-year-old follows his daughter Zoe on to the show after she came third in the 2005 series, and she has since gone on to be the host of spin-off show It Takes Two.
The veteran children's presenter is known to a generation of viewers for his TV shows such as Think Of A Number and Think Again, and he was formerly a host of long-running kids' show Play School.
He is said to have looked "sprightly" during rehearsals for the show which returns to BBC One in just over a fortnight.
Johnny is two years older than Paul Daniels when he graced the dancefloor two years ago.
A show source said: "Everyone thinks he is a really great booking and there is a great affection for him."
The series will also feature former England cricket captain Michael Vaughan and other contestants are said to include Girls Aloud singer Kimberley Walsh and Westlife's Nicky Byrne. Gold medal-winning Olympic cyclist Victoria Pendleton has expressed an interest in appearing on the show.
Last year's Strictly was won by McFly star Harry Judd.