There's plenty of examples of actors changing their looks for a specific movie role, but here's 25 of the most impressive physical transformations ever put on screen. The job of an actor is to inhabit whatever role they are set to play, and the process of doing so can vary greatly depending on the project. It may be as simple as using makeup or changing their hair style, but accents, mannerisms, and the physical resemblance are often left up to the actor to pull off.

These types of physical transformations can be required for roles across all genres. They have resulted in major actors packing on pounds of muscle to play a superhero or athlete or even losing a significant amount weight. In many instances, an actor committing to changing their body can result in high praise and even an Oscar win.

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In Screen Rant's latest video, we take a look at 25 actors who significantly changed their appearance for a role. Whether they gained weight, added muscle, or slimmed down, some of the biggest actors on the planet are included in this list. Chris Pratt and Chris Hemsworth's superhero physiques as Star-Lord and Thor are particularly impressive. Check out the video featured at the top of this post for the full list of entries.

Christian Bale in Vice as Dick Cheney speaking with George W. Bush

One of the clear through lines with this list is the prestigious nature of many with eight Oscar winning transformations included. Natalie Portman won for her slimmed down dancer role in Black Swan, as did Anne Hathaway in Les Misérables, Ben Kingsley in Gandhi, and Matthew McConaughey in Dallas Buyers Club. On the flip side, Hillary Swank's turn for Million Dollar Baby, Robert De Niro's in Raging Bull, and Charlize Theron in Monster are great examples of adding weight helping take home awards. Will Smith's transformation in Ali, Tom Hanks losing 55 pounds for Cast Away, and Rooney Mara in The Girl with the Dragon Tattoo didn't result in a win, but they all did get nominated.

However, the king of the physical transformations is Christian Bale. Even though Jake Gyllenhaal got two mentions on the list for his contrasting looks in Nightcrawler and Southpaw, Bale loses and gains weight regularly for his roles. His only Oscar win came from his skinny look in The Fighter, and he's also received nominations for gaining a substantial amount of weight for American Hustle and Vice. Plus, he's shown the ability to look the part of a superhero through the Dark Knight trilogy, proving there is no look that he can't achieve. His next role in Ford v. Ferrari doesn't require a dramatic change to his appearance though, but early buzz around footage that was recently shown indicates Bale will turn in another great performance regardless.

MORE: Christian Bale's 10 Greatest Roles, Ranked