Russell Crowe
Russell CroweDave J Hogan/Getty Images for Paramount Pictures International

Since catapulting to fame, Russell Crowe has slimmed down and bulked up for multiple film roles. But despite his fluctuating weight constantly making headlines, the Gladiator actor refuses to be fat-shamed.

The Hollywood actor has hit back at critics who commented on his fuller physique after images emerged of him working out while on a break after wrapping filming on The Mummy reboot with Tom Cruise.

The 52-year-old star was pictured doing push ups and a kicking a ball with his son Tennyson in a park in in Sydney's Woolloomooloo. The pair were also accompanied by his wife Phoebe and professional rugby player Sam Burgess, who plays for the NRL Sydney Rabbitoh's for the outing.

For the fitness session, Crowe sported an emblazoned black vest with the text 'The Water Diviner' sleeveless top and matching black shorts.

When a fan revealed that he was the butt of jokes tweeting: "@russellcrowe Howard Stern just goofed on your weight. He said he works hard to 'stay thin and in shape." Crowe hit back: "I can bench press young Howard ... he cannot say the same ..."

Crowe recently revealed that he was trying to shed the weight "For an old boy, it's coming," he said. "I was 121.6 kgs the first week of August last year. I did a movie called The Nice Guys, so I wanted to be the physical juxtaposition of Ryan Gosling. I'm clawing my way back from that."