John Hartson was delighted to meet Conor McGregor at the UFC star's Dublin pub recently.
The Celtic legend shared a photo with the Dubliner on social media, describing McGregor as a "real diamond of a guy".
He said: "Pleasure to meet the Main Man last week.. couldn’t have been more hospitable.. a real Diamond of a guy."
McGregor is back in Ireland as he plots his return to action next year.
The Notorious has been sidelined since suffering a horror leg break in his trilogy fight with Dustin Poirier during the summer.
And his coach John Kavanagh is hopeful that McGregor will be back in the octagon next summer.
The SBG supremo told The Irish Mirror: "It's a case of getting back fit and healthy, get back MMA training and then see what the landscape looks like as we head towards summer - which I'm sure is around about the time he'll be doing that."
On McGregor's recent weight gain, Kavanagh added: "It's funny because if you were talk to any UFC fighter about what can sometimes happen your weight when you're on a bit of time off.
"When you're just lifting weights it's not really unusual to pack on the weight. At the moment he's just working on getting as strong as he can.
"Any strength and conditioning coach will tell you getting fit isn't the hardest thing in the world but getting strong takes time.
"He's getting very strong, and as we come into the gym and start MMA style training - the weight will start to come off anyway.
"But that strength will have a nice conversion into power and then we add the conditioning."
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