Jonny Lee Miller has admitted his testosterone levels have plummeted.

The ‘Trainspotting’ actor, 51, famed for playing Sick Boy in the 1996 Danny Boyle film and who has spent years running marathons and doing martial arts, says turning 50 last year caused his “drive” to collapse.

He told the Daily Telegraph newspaper: “I feel like my testosterone levels are so far down, and I like it, because I’m just way more chill about stuff.

“My focus is my kid and not me. And everything else I get to do is a bonus.

“Just being 50 is like, ‘Oh, f***!’ But I crammed (those years) with really good memories.”

Jonny – who has son Buster, 14, with his model second wife Michele Hicks, 50, and turned 51 in June – was famously first married to Angelina Jolie, 48, from 1998 to 2000.

The pair met on the set of 1995 film ‘Hackers’ about a mob of high school cyberpunks, and Angelina married the actors wearing black rubber leggings and a white shirt, on the back of which she had written his name in her own blood, which she told The New York Times she had drawn out “very carefully” with a “clean surgical needle”.

Despite her wildness, she claimed Jonny was the “wild” one of the two.

He told the Telegraph about how he still loves being physical despite his age: “I dunno, maybe it’s some macho bulls***.

“But I am quite a physical person, I need to do stuff to keep me from getting depressed.”

Along with running marathons and ultra-marathons, Jonny won a Muay Thai fight in the ring in 2019 by knockout.

When asked if he thinks of himself as an “alpha male”, he told the Telegraph: “No, probably Charlie Delta, maybe. You know, I hate that term.

“Anytime someone says, ‘Yeah, it was a room full of alphas’, I’m like, ‘Oh, these f****** guys’.

“I’m not (one), I don’t like to take charge of the situation. I just like to be able to take care of myself and the people around me… I just like to push myself. “And I am a dude.”