Conor McGregor posted a photo of himself alongside Cristiano Ronaldo, both with their tops off, inside the Octagon on Instagram last month.
Cristiano looked like the bigger bloke from the photo, but could he beat the UFC Featherweight champion in a fight?
McGregor was asked this question by BT Sport - and you can probably guess how the self-assured Irishman responded.
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The 28-year-old mixed martial artist is in no doubt that he’d destroy Ronaldo.
Even though they consider each other mates, McGregor admits he’d “slap the head off” the Real Madrid and Portugal superstar if they went head-to-head inside the Octagon.
McGregor: I'd slap Ronaldo's head off
"He didn't get in and spar but he's a nice guy and he's in some shape," McGregor told BT Sport, per Goal. "But there's no competition, I'd slap the head off him.”
The UFC star continued: "He's in tremendous shape. He's a true athlete and a great guy, a good friend of mine. I've been talking to him a long time.
"He messaged me a long time ago on Instagram a good while back because I was wearing his underwear for the [Diego] Brandao fight."
McGregor: The lightning flattered Ronaldo
On the photo that was uploaded to Instagram, McGregor insisted the lighting flattered the three-time Ballon d’Or winner.
"He anticipated the lighting, he was under the lighting and had the abs going, he had the pose,” the fighter added. “I went more lats and he went more abs!"
McGregor: Ronaldo has signed contract extension
McGregor also revealed the news that Ronaldo has signed a contract extension with Los Blancos.
No formal announcement has been made yet, but McGregor’s comment falls in line with what has been reported in Spain throughout this summer.
Asked if he can overtake Ronaldo in the list of top-earning celebrities, he said of the former Manchester United man: ”That'll be tough, he's just signed a new contract with Real Madrid but we'll see, maybe next year I'll have him!"
McGregor will fight Nate Diaz in Las Vegas on August 20.
Ronaldo, meanwhile, is expected to be fit for Real Madrid’s second La Liga match of the new season against Celta Vigo.
Could Cristiano Ronaldo shock Conor McGregor in a fight - or would he get his head slapped off? Have your say by leaving a comment below.