UFC star Conor McGregor says he and his father are being sued by Artem Lobov for defamation in addition to compensation his former training partner is seeking for the sale of the Proper Twelve Irish Whiskey brand.

Lobov, a former MMA fighter, sued McGregor earlier this month, claiming he is entitled to 5 percent of the $600 million sale of Proper Twelve that took place in 2021.

"My client is a retired professional fighter with a master's degree from DCU in Finance and Capital Markets," Lobov's attorney, Dermot McNamara, said. "We have issued High Court proceedings on his behalf to enforce an agreement with Mr. McGregor regarding the Proper No. 12 whiskey brand. My client was the initial creator and co-founder of the concept to launch an Irish whiskey brand associated with Mr. McGregor. As these matters are now before the court, we will not be making any further comment."

Lobov has publicly claimed on a number of occasions that he planted the idea of selling Irish whiskey to McGregor. According to the Russian's account of events, McGregor was initially considering partnering with Game of Thrones actor Hafþór Björnsson on a vodka business. Lobov then presented McGregor with the idea of Irish whiskey instead, which he found to be the better business plan.

“I said to him before you even look any further, ‘Here’s what I know about Irish whiskey.’ I told him about my presentation from college," Lobov told Jordan Ellis of TalkSport. "I told him about the dominance of Irish whiskey and all of that. He said, ‘You go off and see what deal you can put together’ and I went on my way.”

McGregor allegedly offered to pay Lobov $1 million for his work, a deal Lobov declined. A 5 percent stake of McGregor's $600 million sale would be around $30 million.

McGregor has denied the claims, calling Lobov a "rat" in a since-deleted tweet.