Conor McGregor has brought Dong Hyun Kim into his training base ahead of his UFC comeback.
McGregor (22-6) will return from a five-year hiatus at UFC 329 on July 11 when he rematches Max Holloway (27-9).
His preparations have included spars with 'Stun Gun' Kim (22-4-1), the former UFC welterweight contender.
"We got some great training in the past few days," McGregor was overheard explaining to his family as they met Kim, via the South Korean's YouTube channel.
"He was a ferocious UFC competitor in the 170 pounds division. He has a win over Nate Diaz, a win over John Hathaway."
Kim, now 44, has been retired from MMA for nine years after 18 fights in the UFC.
He defeated Diaz via unanimous decision in 2011 and knocked out Britain's Hathaway with a stunning spinning elbow in 2014. He also notably fought divisional veterans Demian Maia, Carlos Condit, Tyron Woodley and Colby Covington.
Now, he is a mainstream TV star in his homeland of South Korea and possesses a YouTube following of more than a million subscribers who have seen him document his time training in Dublin, Ireland, alongside McGregor. His videos have captured footage of their light sparring sessions. Previously, he visited Paddy Pimblett's Liverpool gym.
McGregor, whose rival Diaz lost to Mike Perry on Saturday night in MVP's first MMA event, will remain at welterweight when he fights Holloway.
Their first fight, 13 years ago, was at featherweight when both were up-and-coming talents. McGregor won by decision and injured a knee in the process, before going on to capture titles at featherweight and lightweight.
His most recent three fights have been at 170 pounds, including back-to-back losses to Dustin Poirier. McGregor hasn't fought since injuring a leg in defeat to Poirier in 2021.
Holloway will be stepping up a weight class to meet McGregor, who has already benefitted from his training alongside the veteran Kim.