A trimmed-down Russell Crowe is speaking about his dramatic 52-lb weight loss.

The 51-year-old actor called in to an Australian radio show to dish on losing weight after bulking up for a role opposite Ryan Gosling in “The Nice Guys.”;

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Crowe plays the tough guy partner to Gosling’s private investigator as they track down a missing girl and the murderer of a porn star in the 1970s-set movie.  The black comedy, due in theatres on May 20, saw Crowe top out at 268 lbs during production last summer.

The Oscar-winning actor wanted to pack on the pounds for what he calls a “physical juxtaposition”; next to Gosling’s more slender physique.

Now down to 216 lbs, the weight-loss journey isn’t over for the 51-year-old Crowe, who says he’s still “clawing [his] way back”; from his heaviest weight.

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The actor called into the Fitzy and Whippa radio show after the hosts sang a parody song dedicated to him. After talking  Aussie rules football and his physical transformation with listeners, the actor had a few kind words for “Nice Guys”; co-star Gosling.

“That kid  is a comic genius. He’s great company, he’s really smart, he loves what he does.  He asks all the right questions,”; the actor says of 35-year-old Gosling, who had Crowe doubled-over in laughter on set.  “Working with him was such a treat.”;