Sienna Miller on the 'astounding' way Chadwick Boseman got her paid fairly on '21 Bridges'

Chadwick Boseman helped get Sienna Miller equitable pay on 21 Bridges by boosting her salary out of his own pocket. The actress remembered her late co-star in a special edition of Empire which honours Boseman’s life and legacy. The Black Panther star died in August after quietly battling colon cancer. He was only 43.

“I didn't know whether or not to tell this story, and I haven't yet. But I am going to tell it, because I think it's a testament to who he was,” Miller shared.

Boseman produced 21 Bridges and was “really active” in trying to get Miller on board.

“He was a fan of my work, which was thrilling, because it was reciprocated from me to him, tenfold. So he approached me to do it, he offered me this film, and it was at a time when I really didn't want to work anymore,” the actress said. “I'd been working non-stop and I was exhausted, but then I wanted to work with him.”

Negotiations with the studio stalled when Miller’s desired salary wasn’t met.

Read more: Chadwick Boseman remembered in new mural: 'This one is special'

“This was a pretty big budget film, and I know that everybody understands about the pay disparity in Hollywood, but I asked for a number that the studio wouldn't get to,” she explained.

“And because I was hesitant to go back to work and my daughter was starting school and it was an inconvenient time, I said, ‘I’ll do it if I'm compensated in the right way.’ And Chadwick ended up donating some of his salary to get me to the number that I had asked for. He said that that was what I deserved to be paid.”

Watch: The thrilling trailer for 21 Bridges

Miller declared the gesture “about the most astounding thing that I've experienced.”

“That kind of thing just doesn't happen,” she continued. “He said, ‘You're getting paid what you deserve, and what you're worth.’”

“It's just unfathomable to imagine another man in that town behaving that graciously or respectfully,” Miller added. “In the aftermath of this I've told other male actor friends of mine that story and they all go very, very quiet and go home and probably have to sit and think about things for a while. But there was no showiness, it was, ‘Of course I'll get you to that number, because that's what you should be paid.’”

Miller and other stars remember Boseman in Empire’s tribute issue, out on Thursday.

21 Bridges is now streaming on Amazon Prime Video UK.