The Brit, who was the first choice to play handsome and debonair Christian Grey in this year's (15) Fifty Shades of Grey movie, reveals he dreams of coming face to face with the tough guy.
Hunnam studied MCGregor's moves while he was getting into shape for his new film Knights of the Roundtable: King Arthur, and now he thinks he could be a worthy opponent.
"I'm a huge Conor McGregor fan and I got tickets to go and see him. In my mind I thought, 'Maybe I could fight Conor MCGregor!'" the actor tells TMZ.com.
But Hunnam doesn't expect to beat the UFC champ, adding, "I don't think it would go too well for me. I give myself, maybe, seven and a half seconds before I get knocked out, but it'll be a great seven and a half seconds. I could maybe evade him for seven and a half seconds."
The actor reveals his MCGregor-inspired training regimen really helped him slim down for his latest role in the Guy Ritchie period piece - he now weighs just 140 pounds (63.5 kilograms).
And Hunnam insists he's no soft guy once the cameras stop rolling - he owns a collection of swords and axes and he isn't afraid to use them, should an intruder ever enter his private space.
Talking about his weapons arsenal during a past appearance on U.S. chat show Conan, he revealed he started arming himself at home after spotting a burglar in his back garden.
"I had one of those very cheap garage doors... and it was 11 o'clock in the morning on a Tuesday and the guy just ripped it up... and was just, casual as you like, walking through my back yard looking for ways into my house and figuring out how he was gonna rob me," Hunnam said.
"At this point I only had one weapon in my house and it was a baseball bat next to my bed and so I thought, 'Let's get the bat, see what's gonna happen...' and so I grabbed the bat and I came out... just as he was rounding the side of the house and he stopped and I looked at him and I said, 'So, we got business motherf**ker?' It was so annoying. It turned out we didn't have business, but he was not intimidated at all. He just turned around and, casual as you like, strolled out.
"Then I made it my business to arm myself... I just accumulated (things). I'd be somewhere, at a swap meet or something, and I'd think, 'That will be good'... I got a hatchet, I have a Samurai sword, but I also have a machete, but it's kind of old and rusty."
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