Acting star Sylvester Stallone is rooting for massive underdog Conor McGregor to beat Floyd Mayweather.

Conor McGregor has no chance of beating Floyd Mayweather Jr. in a boxing ring. That's the daily rhetoric we're going to hear from experts in the lead-up to the highly anticipated mega-fight between two of the biggest stars in combat sports history.

Hollywood sensation Sylvester Stallone, however, who is perhaps most well-known for his acting role as Rocky Balboa, is rooting for 'real life Rocky', 'The Notorious', to beat Mayweather on August 26.

"You know who's gonna win. You know who's gonna win!" Stallone told TMZ Sports recently (h/t Ryan Harkness of MMA Mania). "I only got the underdog. It's great for boxing. [McGregor]'s a real life Rocky. But then again ... I live in fantasy."

While most fans and fighters give McGregor little to no chance of even landing a significant strike against boxing's pound-for-pound great, Stallone believes anything could happen on the night.

"[Mayweather]'s gonna get hurt," he said with a wink. "Nah, I'm only kidding. Let's put it this way guys, it's never been done before. Never been done before! So you never know."

McGregor, 28, has devastating power to compliment his precision and timing, but has never stepped foot in the boxing ring. Mayweather, who will be looking to extend his career resume to 50-0, has been competing in the sport since 1996 and has cemented his status as one of the best boxers of all time.

The blockbuster fight is set to take place on August 26 at the T-Mobile Arena in Las Vegas, Nevada.