He was criticised for taking on the role by those who believe that the part could have gone to a transgender actor instead of a cisgender man.
While Redmayne meant no offence, he would leave the role for someone else if he had his time again.
Speaking in an interview with The Times, the 39-year-old said: “No, I wouldn’t take it on now. I made that film with the best intentions, but I think it was a mistake.”
He continued: “The bigger discussion about the frustrations around casting is because many people don’t have a chair at the table.