Conor McGregor, the two-division UFC champion, was seen ‘sparring with the stars’, as he took on former Game of Thrones actor turned boxer, Hafthor Bjornsson.

Bjornsson has previously won both Europe’s Strongest Man as well as World’s Strongest Man and since his sparring session in 2015, has been eager to take on the likes of boxing and further professional fighting.

Yet, outside of this Bjornsson, is perhaps best known for playing Gregor ‘The Mountain’ Clegane, a Clegane knight and fearsome warrior in HBO’s Game of thrones series.

The Icelandic Strongman revealed that he had a sparring session with McGregor in 2015 just before the Irishman's fight against Jose Aldo.

Bjornsson blamed his bulking figure for not being able to keep up with the agile McGregor and highlighted the importance and sheer amount of Cardio involved in MMA fighting, going on to say that:

"There was a time where I had a grab of him and thought, 'I can crush this guy.’"

He also admitted that his athletic ability wasn’t to the same standard as McGregor’s and that "I don’t have cardio for running after small guys."

Speaking on Off the Ball, Bjornsson pulled no punches:

“Bring me some shorts and put us in a cage, I’ll fight again. I had him a few times, but I just didn’t want to break him. I was like, ‘F**k this, I’m not going to run after this small guy!’

"He’s running around, you know? I don’t have cardio for running around after small guys.”

He even went on to say that the MMA fighter ‘owed him’ for not breaking him before his fight with Aldo, a fight that turned heads with McGregor taking a first-round KO against his opposition and thrusting McGregor into the spotlight and exponentially increasing his value in UFC.

Bjornsson himself is also no stranger to the ring, beating professional arm-wrestler Devon Larratt in the first round in Dubai and Bjornsson himself showed on Twitter the steps he had taken towards trimming down in preparation for the fight.

Perhaps Bjornsson’s playful request to spar McGregor again couldn’t come at a worse time with the UFC champion having a discouraging 2021, being beaten in both January and July by American Dustin Poirier and since recovering with a broken leg since the second Poirier fight.

If one thing is for certain, Bjornsson is keen to take up practice with his old sparring partner and perhaps with a new fitness regime and a desire to compete at the highest levels.

Thor Bjornsson may be a worthy opposition to perhaps the best of fighters.