Singer Seal has lost his appeal against an earlier court judgement to award his former manager £500,000 in commission from his first two albums.
The singer married to supermodel Heidi Klum
In the original case last year the star, real name Henry Olusegun Adeola Samuel, had claimed John Wadlow exerted "undue influence" on him.
But in a written ruling at London's High Court, the judge also ordered Mr Samuel to pay Mr Wadlow's legal costs.
The full cost to the singer could be as high as £1 million.
Mr Samuel told the original court that in the five years after he parted company with Mr Wadlow in 1995 he paid him $4 million, which he described as "a substantial amount of money".
A panel of three judges at the Court of Appeal ruled on Wednesday that the management agreement signed by Mr Samuel entitled Mr Wadlow to commission from the albums.
The appeal judges also found that a settlement agreement signed in 1995, when the pair severed links, also entitled the former manager to commission.
Seal is best known for the hits Crazy and Kiss From A Rose. He also had two UK number one albums in the 1990s.