The Avengers actor is producing the film, a drama based on Timothy MCNeil's play of the same name, which sees Matt play a transgender woman who forms an unlikely friendship with a suicidal man.

Following the casting, several people, including transgender actress Jen Richards, took to Twitter to slam the decision to cast a cisgender actor - an actor who feels comfortable with the gender and sex they were assigned at birth - in the role.

But on Wednesday (31Aug16), Mark used his Twitter page to answer the critics, writing: "To the Trans community. I hear you. It’s wrenching to you see you in this pain. I am glad we are having this conversation. It's time."

He also addressed why he had cast his The Normal Heart co-star Mark in the part, adding: "In all honesty I suggested Matt for the role after the profound experience I had with him while making The Normal Heart."

When someone asked Mark if he would consider recasting Matt, he replied: "The movie is already shot and Matt poured his heart and soul into this part. Please have a little compassion. We are all learning."

The criticism of Matt's casting is part of a much wider discussion in Hollywood, following a string of cisgender actors taking on transgender roles - Jared Leto in Dallas Buyers Club, Eddie Redmayne in The Danish Girl and Jeffrey Tambor in Transparent.

In her original Twitter plea, which took place over several days, Jen said that this pattern is contributing to violence against trans women by seemingly suggesting that transgender woman are actually just men pretending to be women and not entitled to be considered in their own gender class.

"Dear @MarkRuffalo & @MattBomer: if you release this movie, it will directly lead to violence against already at risk trans women," she wrote. "You will exacerbate the cultural belief that trans women are really men, which is the root of violence against us. @MarkRuffalo @MattBomer."

As well as this, Her Story actress Jen added that casting cisgender actors in these roles is preventing transgender stars like her from getting work. In fact, Jen even admitted she auditioned for a part in Anything, but wasn't successful.

After Mark's Twitter response, Jen tweeted him saying: "Thank you @MarkRuffalo, this means a lot. I would love to talk to you about it, and how to move forward positively."