Question

تو نقش خودش غرق میشه( برای یک هنرپیشه)

Answer 1

To be/ get immersed in one's role/ character 

 

He/she ( always) gets immersed in his/her character.

 

Emma Watson insists that she got immersed in her character by watching “a ton of reality television".

The actor was immersed in his role completely.

 

Immerse  yourself in sth› 

to ​become ​completely ​involved in something

Comments

Good

http://www.imdb.com/list/ls008315866/

Answer 2

He is drowned / absorbed in his (assigned) role.

 

Answer 3

She/He gets lost in the role.

He gets lost in his role.

He gets so into the role that he is identifying as the character.

Comments

Good

http://www.businessinsider.com/actors-who-refuse-to-break-character-2013-2