Liam Neeson 20-lb weight loss explained: actor asked by Martin Scorsese to 'look gaunt' for movie; see 5 other actors who've drastically lost weight for a film role

Liam Neeson explains that his 20-lb drastic weight loss was for a role and director Martin Scorsese requested that he and his fellow actors "look gaunt" for a film.

The "Taken" actor was photographed looking dangerously thin in the summer this year and the 63-year-old actor finally revealed why he looked that way. The weight loss transformation was for Martin Scorsese's new movie, "Silence."

"Martin wanted us all to look a bit more gaunt, which [stars Adam Driver and Andrew Garfield] did as well," Neeson said at the 4th Annual Los Cabos International Film Festival, as reported by Yahoo. "I know Adam went to the extreme. He's an ex-Marine, and when he's given an order, he follows it through. He was like something out of Auschwitz."

"Silence" is a movie about two Jesuit priests who went to Japan to spread Christianity but were persecuted instead. Neeson plays Father Cristovao Ferreira, a Portuguese missionary, Daily Mail reports.

"Silence" is set to be released in 2016.

Neeson isn't the only one who took great dedication for their craft by losing weight to prepare for their role. Here are 5 more actors who drastically lost weight for a movie role:

1.) Christian Bale

Bale who starred in both big name movies such as "The Machinist" and "Batman Begins" dropped and gained weight to suit his role. He told BBC that he dropped to 122 pounds for his role in "The Machinist" even though he wasn't asked by director Brad Anderson to do so. To play for Batman, he then gained around 100 to play the Caped Crusader. He admits to PEOPLE that he "adjusts for what is needed," he adds "but only if I have quite an obsession about that role."

2.) Charlize Theron

The actress was highly praised and even won an Oscar award for best actress for her role in the 2003 film "Monster" where she portrayed a serial killer. According to Business Insider, she then shed excess weight to prepare for her role in "Head in the Clouds."

3.) Anne Hathaway

According to Telegraph, Anne Hathaway lost 10 pounds in three weeks for her role in "Les Miserables." The star lost 15 pounds more and a lot of her hair during the filming of the musical.

4.) Tom Hanks

Tom Hanks shed 50 pounds for one of his most famous roles as a man stuck on an island in "Cast Away." US Magazine reports that the actor was diagnosed with type 2 diabetes and blamed the drastic gaining and losing of weight or yo-yo dieting.

5.) Chris Hemsworth

Most famously known for his role as "Thor" and as Liam Hemsworth's big brother, Chris dropped his weight for his role as a "shipwrecked man at sea" in the movie "In the Heart of the Sea," according to Fox News.