Noel Edmonds has formally kick-started his legal action against Lloyds Bank as he enters the I'm a Celebrity jungle.
The TV personality is seeking at least £30m over an alleged scam involving staff at the Reading branch of HBOS, which was later bought by Lloyds.
He claims his former firm Unique Group was destroyed because of fraud. Lloyds has rejected the basis of his claim.
On Friday his lawyers served Lloyds with a pre-case letter to initiate action, which could start next month.
A spokesperson for Lloyds Banking Group said it would review the letter before responding.
"We fully understand the anguish he feels at the failure of his businesses, but on the information we have seen so far we simply cannot agree that this is the result of actions taken by the former HBOS business.
"We are content for the matter to be considered by a court if he pursues his legal action. However we cannot allow ourselves to be pressed into paying out money without cause just because an individual uses their celebrity status to attack us."
The spokesperson said 71 of the 72 customers affected by the fraud at the HBOS Impaired Assets office based in Reading have been made compensation offers and 64 had been accepted.
It comes as Mr Edmonds says he will use his appearance in the ITV reality show to promote his cause in his battle for compensation from Lloyds.
The former Deal Or No Deal host said in videos released to the Press Association that Lloyds would "have to pay up", adding: "I am totally convinced at trial we will win."
"It's not going to do any harm to be in the jungle on ITV at peak time every single day for a few weeks," he said.
Lloyds has set aside £100m for victims of the fraud at the hands of HBOS Reading staff between 2003 and 2007.
Corrupt staff from the HBOS branch were jailed last year for a £245m loans scam between 2003 and 2007 that destroyed several businesses.
It was revealed they squandered the profits on prostitutes and luxury holidays.