Last year, Beats Audio was bought by Apple for $3 billion, making co-founders Dr. Dre and Jimmy Iovine two of the richest cats in town.

Mo money mo problems, as somebody once said, and now the duo is facing a huge lawsuit from a former partner.

Tech firm Monster assisted the pair with the design of their famous headphones. However, Beats' relationship with Monster soured in 2012, and they ended their partnership. Dre and Iovine then bought out Monster's share in Beats in 2013, not long before they sold the entire company to Apple.

This is what the USA Today had to say about the lawsuit:

The suit, filed in San Mateo (Calif.) County Superior Court, charges that the Beats co-founders concealed the role of Monster and [Monster CEO Noel] Lee in designing and engineering the headphone line, as well as educating them about engineering, manufacturing, distributing and selling the headphones that Monster and Lee invented. After severing ties with Monster, Beats was purchased by Apple for $3 billion. But as the Beats co-founders made millions, Monster lost millions from its investment in the rise of Beats, the suit charges. Had Lee retained his original 5% interest in Beats, his total stake in the Beats-Apple deal would have been worth over $100 million, the suit alleges.