Richard in family tree hunt.
He revealed on micro-blogging site Twitter: "Right, done all my US visa paperwork for Who Do U T U R, photo etc".
The show, first aired in 2004, has been a massive success and has been adapted for international audiences including America, South Africa and Sweden.
Tears Newsnight's Jeremy Paxman was moved to tears after hearing about his great-grandmother's povertystricken life.
And Sex And The City star Kim Cattrall discovered that her grandpa was a bigamist who abandoned his family.
A BBC spokeswoman said: "We will be announcing the names of the stars for the next series in due course."
Madeley presented This Morning on ITV for 13 years with wife Judy Finnigan before the pair moved to Channel 4 where their show, Richard & Judy, ran for seven years.