“Ray” allowed Regina King to tackle one of the most complex and compelling roles of her young career — Ray Charles’ mistress and backup singer Margie Hendrix.

It also afforded her the opportunity to cross off three items from her professional wish list: collaborating with director Taylor Hackford, co-starring opposite Jamie Foxx and acting in a period piece.

“Working with Taylor had been on my list for many years, after seeing ‘An Officer and a Gentleman,’ ” reflects King.

Hackford read the part of Ray when King auditioned for the pic, which she thought odd at first. “The first time is usually with a reader,” she says, “but after I finished, it made total sense to me. This man has been nurturing the project for years. The only person who knows this story better is Ray Charles himself. If I couldn’t connect with him, I wouldn’t be able to connect with any actor.”

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Her bond with Foxx was equally strong.

“It’s really lucky when you have chemistry with the person. That knocks out a lot of the apprehension,” says King. “Once we got together, it was explosive. You know that person has your back and they’re going to pick it up and where they might fall short, you’re going to pick it up.”

Transporting herself 50 years back in time to play the former Raelette was a welcome challenge for the actress.

“It’s very rare that roles like this come along,” relates King. “For many actresses, we find ourselves in the position of repeatedly doing romantic comedies, and I’ve been lucky enough that I haven’t been pigeonholed. When this came up, there were three fully developed roles (for women), which made it very attractive.”

King didn’t meet Charles before filming and, with Hendrix long deceased, she immersed herself in the music and relied on Hackford to fill in the blanks.

“I listened to her music over and over because there is not a lot of information on Margie. Her voice was so powerful, so I just let that guide me,” says King. “Ray told Taylor there was no other woman like Margie, even though she was not well-received in that era, where women were supposed to be seen but not heard. Taking that music and listening to that powerful voice let me know this woman was a force to be reckoned with.”

As is Regina King.