Ryan Reynolds' daughter convinced him to star in the upcoming movie 'Detective Pikachu'.

The 42-year-old actor voices the beloved Pokémon character in the new movie and the film's director Robert Letterman revealed it was his two-year-old daughter Inez who wanted him to take on the role.

Robert told Collider: ''We were all in on Ryan. So, what happened was, I did these tests. I took an old clip of Ryan from a different movie and we animated Pikachu to it.

''And the second I saw that test it was done. It was perfect. We hadn't even reached out to him. There would be no other version in my mind.

''And when he finally said ''yes'' it was a massive sigh of relief!

''And then I found out, he finally confessed, he showed that clip to his daughter and she was the one who talked him into it.

''So thank you to Ryan's daughter!''

Ryan - who also has four-year-old James with wife Blake Lively - stars alongside Suki Waterhouse, Ken Watanabe, Kathryn Newton and Rita Ora in the Pokémon action adventure.

And Robert is delighted that the franchise - which came out in 1996 and is a collective brand for games, toys, films and shows that involve catching imaginary creatures - is popular amongst both new and old fans.

He said: ''First of all, we dedicated the movie to the fans. There's the new generation of fans and there's also the older generation.

''And I was surprised myself how much millennials adore this franchise. The 20 somethings or 30 somethings they grew up with it, they love it.

''It's a love letter to fans of Pokémon but also it's also a human story and amazing journey and its funny and Ryan is hilarious and Kathryn is incredible.

''And the emotional ride of it and the heart of it I think is appealing to everyone whether they know Pokémon or not.''