Russell Simmons and brother Rev Run's business partner has declared war. He is claiming they've kept MILLIONS in profits from their kids shoe company and now, he's up to sue.

The lawyers for "Rasheed Young", President of Run Athletics sent Russell and Run a letter back in November, accusing the brothers of secretly funneling millions in revenue from their Pastry brand into a company that Rasheed isn't a part of.

Rasheed claims Pastry has ranked in tens of millions in sales and so far, he hasn't seen a penny of it.