Sebastian Stan sweats it out for his upcoming '355' movie

'The Avengers: Endgame' star Sebastian Stan is prepping hard to get into the skin of his character for upcoming film '355'.

The 36-year-old on Friday shared as a picture of himself, flaunting his six packs on Instagram.

"After 7 years with @donsaladino I caught a good day, sucked it up and finally posted this..." Stan wrote as the caption.

"Been working with this guy through years of self judgement [sic] and mental wars when it comes to fitness and LIFE, and TODAY I'm giving myself a break and acknowledging the hard work we've done for @355movie (and this other small thing we got comin' ) !" he wrote further.

"Proud of what we've accomplished pal! Love you. And thank you. #donsaladino #drive495 #355movie#marvel#TheFalconAndTheWinterSoldier," he added.

Along with Sebastian Stan, the film also has Jessica Chastain, Diane Kruger, Lupita Nyong'o, Fan Bingbing, Penelope Cruz, and Edgar Ramirez.

The upcoming thriller is being directed by Simon Kinberg, who has previously helmed 'Dark Phoenix'.

The film revolves around Chastain, Nyong'o, Cruz and Fan, who play spies from international agencies around the world. These women must bond together, overcoming their suspicions and conflicts, to use all their talents and training to stop an event from occurring that could thrust the teetering world into total chaos.

Along the way, these strangers and enemies become comrades and friends, and a new faction is formed - code-named '355' (a name they adopt from the first female spy in the American Revolution).

The movie is being produced by Chastain through her Freckle Films banner alongside Kelly Carmichael and Kinberg.

( With inputs from ANI )