O’Toole wished McGregor well against Aldo, and then executed some seriously impressive muscle-ups.

In case you didn't know - the muscle-up is an agonisingly difficult training move that is essentially a pull-up followed by a dip. It is used to take yourself from below a sets of rings or bar to above a set of rings or bar.

There are few 24-year-olds who can do it, never mind 64-year-olds.

McGregor was so impressed he posted his own video, acknowledging O’Toole’s phenomenal skill.

If you cannot see the embedded Facebook video check it out here.

“Willie O’Toole I got your video,” McGregor said. “I was absolutely blown away.

“64 years of age, an absolute inspiration.”

The Dubliner said many of the fighters training with him could not do what O’Toole could, and then demonstrated a few muscle-ups of his own.

“There you go brother, still not with the technique you have!” he admitted afterwards.

“Whatever you're doing, keep doing it my friend, thank you so much.”