Actor Russell Crowe is unrecognisable after putting on a lot of weight for his role in the new film "Boy Erased".

Crowe, 53, was seen running errands in the city here with a big paunch and fuller face, reports thesun.co.uk.

Best known for playing the lead in "Gladiator", he looked casual in a pair of chinos and a white T-shirt.

The Australian star is playing a baptist pastor in the film adaptation of the book "Boy Erased: A Memoir of Identity, Faith, and Family" by Garrard Conley. He features alongside actress Nicole Kidman.

The movie tells the story of Jared (played by 'Manchester by the Sea' star Lucas Hedges), the son of a Baptist pastor in a small town.

He is ousted by his parents (played by Crowe and Kidman) at the age of 19 and is given an ultimatum -- he can either do a gay conversion therapy programme or be expelled from the community.

It's not the first time Crowe has lost or gained weight for a film role as just last year he bulked up for his role in "The Nice Guys".

He managed to lose the 24 kg in just seven months and in March last year, he was down to 98 kg.