Martin Freeman, who reprises the role of Everett K Ross in Black Panther, feels superheroes have to be believable.

"Marvel superheroes are all grounded. Clearly, it's a heightened world and clearly, it's not a kitchen-sink drama. But the acting still has to be real," says Freeman. "You have to believe in the characters. And what two characters are doing to each other at any given time has to stand up, even while people knock down buildings and fly and stuff," he adds. 

Freeman, who first appeared in Captain America: Civil War, says he was not really familiar with the superhero Black Panther. "I didn't grow up as a Marvel comic book reader particularly. I knew of Black Panther, but I couldn't have quoted chapter and verse at you."