Conor McGregor just got even richer. The UFC star and his business partners sold their majority stake in Proper No. Twelve Irish whiskey to Proximo Spirits in a deal that is worth up to $600 million. Proximo Spirits, which also owns Jose Cuervo and Bushmills, in addition to other brands, already had a 49 percent stake in Proper No. Twelve Irish Whiskey. Now, it owns a much bigger stake -- the size of which is unknown still.

As McGregor's business partner Ken Austin told Shanken News Daily, it was the plan all along for Proximo to eventually buy a majority stake in the company.

"When we started this business with Proximo, we basically laid out, I'll call it certain hurdles, that would allow them to buy pieces of the company over time," Austin told Shanken News Daily. "We hit a milestone and it gave Proximo the opportunity to own a significant stake."

McGregor celebrated the sale in an Instagram post, noting that "Proper Twelve is my baby for life."

The UFC star is still going to be the company's spokesperson after the sale goes through and will continue to appear in the majority of the television commercials for Proper No. Twelve.

"Conor is very, very fixated on this being a multimillion-case brand," Austin told Shanken. "I wouldn't count him out ever."