Colin Firth looked shockingly slimmer in his role of Mark Darcy in "Bridget Jones's Baby." Actually that weight loss was first remarked on in 2013 when fans were prompted to inquire if the "King's Speech" actor was ill. Firth's wife Livia Giuggioli explained then that her husband's skinny look was just temporary. But the third film in the "Bridget Jones" trilogy confirms that Colin is still startlingly smaller. Here's the surprising secret to his weight loss.

The diminishing Mr. Darcy

As Mr. Mark Darcy in "Bridget Jones's Diary" and Mr. Darcy (Fitzwilliam) in "Pride and Prejudice" Colin Firth cut a dashing figure--lean, haggard, enigmatic, kind-eyed.

He was never what you could call obese or even overweight but he was definitely more avoirdupois. Now it later films Firth has literally been whittling away, the firm jaw becoming chiseled, the skin more taut and the face almost skeletal. Did Firth perhaps get a face lift, folks wondered? Or, worse yet, was he wasting from some sort of secret, mysterious illness? No, his wife assured, he was just dieting for a role in the spy thriller/comedy "Kingsman: The Secret Service" by Matthew Vaughn. She said he'd be off the diet and back to normal after Christmas.

So why and how does Firth maintain weight loss?

Well, Christmas came and went a few times and still in 2016, Firth is trimmer. The Oscar winner and multi-decorated CBE (Commander of the British Empire) has done films since "Kingsman"--"The Railway Man" and "Devil's Knot" to name a few--and his weight was not remarked upon.

Firth did wear a beard for "Devil's Knot." In "The Railway Man" he played atorturedPOW with PTSD so everyone was prepared for him to look thinner. Wearing dark-rimmed Bill Nighy style glasses seemed to make the weight loss more apparent.

Does Colin like his new look or is it in anticipation of another role? "Kingsman: The Golden Circle" comes out in 2017 so that could be it.

Firth has based his method of acting on getting inside a character's head. To play POW Eric Lomax, he had to get first-hand understanding of life in a Japanese prisoner of war camp. Perhaps, like Liam Neeson and Timothy Spall, getting inside his character's skin is part of that process.