Conor McGregor lacks the necessary boxing skills to swap the octagon for the ring, believes former WBO middleweight champion Andy Lee.
UFC star McGregor was granted a boxing licence in California last week and has repeatedly called out retired five-weight champion Floyd Mayweather.
Lee admits the Dublin fighter's exploits have earned his respect but doesn't believe UFC's first two-weight champion is anywhere near the level of Mayweather.
"I wouldn't know about the UFC as a whole, because I don't really watch a lot of it. I'm a big fan of Conor McGregor in terms of what he's done as a person, he's a cultural phenomenon," Lee told newstalk.com.
"Out of interest, when he's posted a video of himself sparring, I've watched it, and to me, technically, it's not top level, it's not up to scratch.
"He can fight, he's good with his hands. But, in terms of boxing, it would be interesting to see if he could win an Irish professional title. That wouldn't be the highest standard in the world, but it would be an interesting level.
"I don't see him as a top level boxer in any way, but in terms of the UFC he probably is because the level wouldn't be so high."
Lee, who held the Irish super middleweight title in 2007, was asked whether the prospect of McGregor facing Mayweather in the ring was laughable.
"In terms of a contest, yes," added Lee. "But in terms of a money-generating event, it would be the biggest event of all time."
"Look, he's a young guy from Co. Dublin and not so long ago he was on the dole and now he's making millions and millions.
"As an Irishman, he carries the flag into the ring, and I have to take my hat off to him and say 'look, I respect everything you're doing."