"She said she did a photo session with New York magazine," Hackford told PEOPLE at Tuesday's New York premiere of Love Ranch, which he directed. "I had no idea what they were until I saw them in the magazine."
The photos, which Hackford says he "loved," correspond with Mirren's role in Love Ranch as the madame of a legalized brothel.
Mirren's take on it is slightly different. "He loved them because he recognized me in them. That's the Helen that he knows," she tells PEOPLE of the shot which is "as naked from the neck up as it is from the neck down."
They do agree on the context, however. Hackford explains the shoot was more about art than nudity as Mirren, 64, is very interested in art photography. She says, "The intention was not to make a sexy photograph, the intention was to do a bare photograph."
Love Ranch, which is in theaters now, is the first time the couple has worked together since they met on the set of White Nights 26 years ago. And it is no accident. After years of hoping to work with his wife again, this time Hackford, 65, says he "consciously went out and looked."
"She played two different queens of England, two different Elizabeths, in the same year," says Hackford. "And I know as a director that's how you seduce actors – you give them something [different]."
Her role this time, Mirren says, is "not a sexy role, it's not. It's about love. A brothel, believe it or not, is not a very sexy place."
With reporting by ULRICA WIHLBORG
For more on Mirren embracing her sexy side and starring in Hackford's films, pick up the new issue of PEOPLE on newsstands now