Katie Holmes supports husband Tom Cruise at the Valkyrie premiere

Katie Holmes has set the record straight about her dramatic weight loss.

The actress sparked fears for her health when she stepped out looking super-thin at the Valkyrie premiere in Brazil last week.

But Katie, 30, blames her role in Broadway show All My Sons for her slender figure.

My metabolism was in full gear the whole time, she tells Hello! I lose weight fast when Im working so hard. It doesnt matter how much I eat, I just get thin.

But Kate, who has 2-year-old daughter Suri with husband Tom Cruise, 46, doesnt mind too much.

Its not the worst problem in the word to have, though, now is it? she adds.

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Alison Adey