Kristen Stewart is to star in 'Love Lies Bleeding'.

The 'Spencer' actress has boarded the cast of the romantic thriller that is being directed by Rose Glass, the filmmaker behind the acclaimed horror flick 'Saint Maud'.

Insiders say that the story is centred on the extreme qualities it takes to succeed in the competitive world of bodybuilding.

Kristen will play the co-lead in the movie – the protective lover of a female bodybuilder.

Sources are, at this stage, describing the project as a romance fuelled by ego, desire and the American dream.

A24 is backing the movie along with Film4, the features division of the British TV network Channel 4.

Glass has written the script with Weronika Tofilska and film bosses are hoping to cast the lead as authentically as possible with the search currently underway.

Kristen was nominated for the Best Actress Oscar for her portrayal of the late Princess Diana in the movie 'Spencer' and she confessed that she was "astounded" to be recognised by the Academy.

The 32-year-old star said: "I am truly astounded and unbelievably moved and touched and just stunned. I love this movie.

"I just saw the director of 'Spencer' [Pablo Larraín] for the first time since we found out about the nomination, and just seeing the look on his face, seeing all the work we've put into this just evident in his smile, it made me so happy."

Regardless of the Oscar nod, Kristen still had a "really stunning" experience during awards season as the movie received a lot of plaudits.

The 'Twilight' actress said: "I've never even gotten kinda close. So this experience alone, even without the nomination, would have been really stunning."