The pair played brother and sister in Enola Holmes and the film's

sequel, and Millie has been open about their friendship - insisting

that they have a strong bond despite their 21-year age difference,

with the actress dating the 39-year-old Man of Steel. applauds that he is "hard" with her.

"Henry and I felt like we were in a real adult relationship.

Such a really good friendship, really healthy. One where we had terms and conditions.

I know Henry. have business requirements with me.

Millie then explains that one of Henry's conditions is that he is forbidden

"I'm not allowed to ask about his private life. It's like, 'Honey, shut up.