Hugh Grant claimed he only went into acting "to be famous and make a lot of money".

The Substance actor shocked his Dungeons and Dragons: Honor Among Thieves co-star Justice Smith with his candid confession and the 30-year-old star is still unsure whether or not he was joking.

During an appearance on the What Are We Even Doing? podcast, host Kyle MacLachlan asked Justice if he had got along with Hugh during filming.

He replied: "I did. Oh, I love Hugh.

"When I worked with him, I was like, 'Hugh, you know, do you still love what you do? Do you still love this?'

"And he was just like, 'No.' He said, 'I've never loved it.' He's like, 'I just wanted to be famous and make a lot of money.' And I said, 'Really?' He said, 'Yeah.'

"He is so funny. And he's like, 'I've always hated the acting part of it.' And I was like, 'Oh.' But he said it with such sincerity."

Justice was so "stuck" on the conversation, he brought it up with Rosamund Pike while filming Now You See Me: Now You Don't to get her take on whether Hugh was being serious or "just British".

He recalled: "She's like, 'No, I'm pretty sure he's just British.' I'm like, 'Are you sure?' I think 'cause it stuck with me. I was like, 'Oh, I guess you can be a really good actor and just want to like just do it for the fame and money.'"

Both host Kyle and his guest agreed the 62-year-old star is a "perfectionist" and pushes himself hard with his work.

Kyle said: "Here's the thing about Hugh that I think I 'cause I got a vibe about him.

"I've known Hugh for a long time, and he has the same spiel that he does. I think the thing that is so challenging for him is that he's such a perfectionist, and he takes it so seriously.

"It's like everything, he wants it to be perfect. You know, he's got, I think, control issues, but I feel like it's the torture of that experience as opposed to kind of letting it all go and just, you know, doing what he does. But I got to believe that he finds joy in it."

Justice ultimately concluded that Hugh's proclamation was a sign of just how great an actor he is.

He said: "I would hope that he was joking, but also that British humour is so dry and like sometimes hard to permeate that I don't know 'cause he was so sincere.

"Then I watch him...he does the work, he puts a lot of effort into what he does. We were working on a silly comedy together, and you could tell he really cares about it.

"He's such a good actor, he'll make you believe that he doesn't."