The founder of Glastonbury Festival, Michael Eavis, has said booking the Wombles was "a bit of a mistake".
He said: "I've got about 25 stages and managers and bookers for each of the stages. I can't control every single one of them but I do get cross about that kind of thing."
Wombles band creator, Mike Batt said: "He probably doesn't realise what a fantastic live act the Wombles are."
In the 1970s the group had nine hit singles and four gold albums.
The hour-long set on the Avalon stage on Sunday 26 June will feature hits such as Remember You're a Womble.
Mr Batt said he was a "bit surprised" to hear the comment, as the band had been practising hard for the festival.
"Uncle Bulgaria told me he thinks Mr Eavis is probably perfectly aware that festivals like his are so popular because they offer an eclectic mix for everybody.
"It isn't very nice to think that you have been booked at a festival where you aren't welcome, but we hope Mr Eavis will pop along to the Avalon stage on Sunday to check out the reaction for himself.
"We might even give him a glass of Madame Cholet's special dandelion cordial.
"Contrary to what he says, the Avalon is a substantial stage and there is huge excitement about the Wombles' appearance."
Songwriter Mike Batt created the band based on the BBC children's television series which featured a family of furry creatures living on Wimbledon Common who were passionate about collecting and recycling rubbish.
The original characters were created by Elisabeth Beresford in 1968.
This year's three-day festival takes place from 24 to 26 June and headliners for this year include Beyonce, U2 and Coldplay.