Letitia Wright attends the Avengers: Infinity War fan event in London. Picture: Reuters

Letitia Wright - who played Shuri in 'Black Panther' - has revealed that she improvised one of the best lines in the Marvel film.

The 24-year-old actress starred as Shuri in the widely acclaimed Marvel movie, and Letitia has revealed she took it upon herself to create one of the film's most memorable moments.

Speaking to Yahoo Movies, she shared: "When you see T'Challa bring back Ross she says, 'Great! Another broken white boy for us to fix!' that was my idea.

"I said 'Bro, can I say this?' I said to Ryan [Coogler, the director], 'can I say it, because it links to Bucky Barnes being in Wakanda?' and he's like 'perfect, say it.'"

Bucky Barnes - who starred in the 'Captain America' movies - was the original broken white boy.

And Letitia was thrilled that the pair were able to share the final post-credit scene of the film.

She explained: "I was so grateful for that, super grateful. It looked a bit romantical, right? Shuri has a big heart."

Letitia refused to research the character of Shuri prior to her audition for the role.

But, as it transpired, her performance still had strong echoes of how the character was portrayed in the Marvel comic books.

The actress recalled: "It's funny because when I first got the script and just started going to the auditions, something in my spirit said 'don't look at the comics' just go off what the script said.

"I actually, without even knowing it, was playing Shuri from the comic book in my audition.

"So I was being very serious. Shuri was always in competition with her brother she just wanted the throne, from the moment you meet her, but before even reading [the comics] I was already in that mindset of like she's serious about Wakanda, she should be taken seriously, and she doesn't have time for games or messing around."