Last month (May16), the Black and Yellow star lodged a lawsuit against Grinberg and his Rostrum Records label, claiming the executive mismanaged his accounts and profited at his expense.

Under his deal, Khalifa was exclusive to the Rostrum label, and Rostrum would share the income he earned through songwriting, touring, and merchandising. However, in his lawsuit he claims that Grinberg failed to disclose there were alternative options that could have been more beneficial for the musician.

Khalifa, who dropped Grinberg as his manager in 2014, is seeking compensatory and punitive damages of more than $1 million (£743,000), but he may end up losing millions now that Grinberg is alleging the hip-hop star owes him millions.

In legal documents obtained by Billboard on Wednesday (29Jun16), the music executive claims that in 2005, Khalifa signed a deal which stated Rostrum is entitled to receive 15 per cent of all his music royalties and touring profits, as well as 20 per cent of merchandise sales.

In Grinberg's documents, his former client's lawsuit is also described as an "attempt to evade paying millions of dollars" that he owes to his record label.

Grinberg also shared his disappointment in Khalifa in a statement to Billboard, which reads: "To give everything you have to an artist and then be on the receiving end of a fabricated lawsuit is deeply disappointing. What was alleged is, in fact, the complete opposite of our actions and the antithesis of what Rostrum Records and I stand for. Rostrum looks forward to quickly addressing these baseless claims so we can continue to focus our energies on our artists' success."

Grinberg will be taking the claims to a Los Angeles court hearing on 1 August (16).