Beyonce has taken full control of Ivy Park – the clothing brand she launched with Sir Philip Green two years ago.
The takeover comes as the billionaire retail tycoon, who owns Topshop, fights challenges to his reputation.
Sir Philip has strenuously denied allegations that he sexually harassed and racially abused staff.
News of the deal was confirmed in a statement by Ivy Park, a fitness and athleisure brand that sells items such as hoodies and leggings.
The statement suggested that Beyonce had been trying to gain full ownership of the company before Sir Philip was named as the businessman behind an injunction against The Daily Telegraph.
The newspaper had earlier reported that an unnamed businessman had been granted an injunction to prevent them publishing the allegations.
He has strenuously denied the claims – and last month, said in a statement: "To the extent that it is suggested that I have been guilty of unlawful sexual or racist behaviour, I categorically and wholly deny these allegations.
"Arcadia and I take accusations and grievances from employees very seriously and in the event that one is raised, it is thoroughly investigated."
Ivy Park's statement said: "After discussions of almost a year, (Beyonce's) Parkwood has acquired 100% of the Ivy Park brand."
It gave no details on the financial sums involved in the agreement – first reported by the Financial Times – but added that Sir Philip's Arcadia empire would fulfil existing orders.
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Ivy Park shares its name with Beyonce and husband Jay-Z's daughter Blue Ivy.
Sir Philip's agreement with the former Destiny's Child star followed a similar deal with music mogul and TV talent supremo Simon Cowell, who told The Sun newspaper earlier this week he had bought Sir Philip's interest in his Syco operation.