Media
It comes days after consultants Deloitte concluded the show wrongly took £4m in premium-rate phone-ins.
The fake appearance is said to have happened in February 2003. A fan wrote to the show's Jim Didn't Fix It slot and asked to meet The Wurzels.
Producers brought in the band but the fan did not turn up. Sil Willcox, Wurzels manager, allegedly suggested George Allen, the band's record producer, play the fan instead.
He was introduced as George Adams, according to the Daily Mirror, and interviewed by And and Dec.
Willcox told the paper: "They knew it wasn't a real fan." Allen added "Sil asked me to do a favour. So I went on the show."
A spokesman for the presenters said they were not aware of it while ITV said it was "looking into" the claims.
More: Media, Broadcasting
TV Ratings
Big Fat Gypsy Weddings takes nearly 4mThe return of Big Fat Gypsy Weddings draws more than 4.8 million viewers.
Tube Talk
'Simpsons' ultimate countdown (15-11)The countdown of the greatest Simpsons episodes continues.
US TV Ratings
'Cougar Town' returns to ABC with 4.8mAll five major networks were down on Valentine's Day, with ABC suffering the most.
TV Interviews
'Upstairs Downstairs' Neil Jackson Q&ANeil Jackson chats to Digital Spy about Upstairs Downstairs series two.
