The 63-year-old actor will star in the DC Extended Universe sequel as The Thinker and Margot - who reprises the role of Harley Quinn in the film - is convinced the former "Doctor Who" actor will do "justice" to the part.
"The character is definitely done justice," Margot told Den of Geek. "He's such an exceptional actor and he's such a lovely guy ... It's funny, it's a huge cast, but we really all did do a lot together. I don't want to give away anything, so I won't tell you what to expect, but he brings gravitas to the role."
"I've just got to say what an amazing experience it was, in regards of (director James Gunn) and all of (my co-stars)," he said. "You know, the atmosphere on that set was so positive and what a warm, wonderful supportive place to be."
"Not everyone has been in a big superhero movie, even if they've been Doctor Who or anything like that. So to walk on to a set like that can be quite intimidating. But the welcome that (everybody) provided was just fantastic."