Singer-songwriter Seal has been ordered to pay his former manager commission on earnings from his first two albums.
Seal's wife, model Heidi Klum, is pregnant with their second child
A High Court judge ordered the singer, real name Henry Olusegun Adeola Samuel, to pay John Wadlow £500,000.
Seal, famous for hits such as Crazy, had contested the case brought by Mr Wadlow over allegedly unpaid commission on two albums recorded before 1995.
Judge Charles Gray said there was "no doubt" that Mr Wadlow had helped Seal to build his early career.
Seal, 43, who lives in New York, was not in court for the decision.
Mr Wadlow claimed he was entitled to unpaid commissions due under an agreement they signed in 1995.
Both of the albums in question, which were both entitled Seal, were recorded in 1991 and 1994.
Mr Justice Gray was only asked to deal with the question of liability during the trial, not to assess the sum owed, and ordered Seal to make an interim payment of £500,000 and £175,000 costs.
The full amount to be paid to Mr Wadlow will be decided at a future court hearing.
Mr Justice Gray ruled that Mr Wadlow's entitlement to commission arose under a settlement agreement signed in 1995.
The purpose of the agreement was to implement Seal's wish to bring to an end his longstanding relationship with Mr Wadlow, he said.
The judge ruled that the settlement agreement replaced a 1990 management agreement "and the effect of it is that Mr Wadlow has a continuing entitlement to commission in respect of the first and second albums".
Both Seal and Mr Wadlow gave evidence to Mr Justice Gray.
He said he found Seal an "impressive witness" who felt betrayed by Mr Wadlow.
"His answers in cross-examination were thoughtful, modest and fluently expressed," he said.
"It appeared to me that, at least in the early years of his career as an artist, he had little interest in its financial aspects and preferred to concentrate on his music."
Judge Gray added: "I found Mr Wadlow to be a reliable witness.
"His recollection of events, whilst far from perfect, was for understandable reasons better than that of Seal.
"I suspect that his involvement in the music business came about as a result of his love of music rather than a desire to make money."
He added that Mr Wadlow had "felt himself entitled" to share in Seal's success once he became an international star.
Mr Justice Gray ruled that in relation to the 1990 management agreement Mr Wadlow had "misused his influence over Seal".
But the March 1995 agreement was "plainly not procured by undue influence".