Ryan Reynolds' daughters don't ''fully'' understand that their dad is voicing Detective Pikachu.

The 42-year-old actor plays the titular character in the first live-action Pokemon franchise movie and has joked that the reason his girls, four-year-old James and two-year-old Inez, are ''100 per cent psyched'' for one of his movies for the first time, is because they haven't quite worked out it's him in the role, though they think Pikachu does ''sound like'' their dad.

He said: ''This is the first time in my life that my kids have been 100 per cent psyched to see something I'm in.

''Maybe the trick is that they haven't put together or fully understood that it's me doing the voice.

''My daughter James did say that I sound like ... she's like 'daddy, you sound like Detective Pikachu!'''

The Canadian star - who shot most of the film in motion capture on sets all over the world - wasn't able to bring James on set and he won't tell her it's actually him until she and her sister have seen it.

He told 'ET Canada': ''She never actually saw me interacting with any of these people or Pokemon so, she doesn't really know ... and I'm not going to correct her. So, I'm going to let her see the movie, and then I'll reveal.''

Whilst his kids are pumped for the movie, their mother Blake Lively, 31, isn't as impressed.

The 'Proposal' actor said: ''I don't think she was anything beyond mildly amused.

''When a movie starts it's all sort of a dream, there's no like, nothing to grab onto yet ... particularly this movie, which I spent only three days on set, and the rest of the time was that motion capture performance.

''They would just come to whatever set I was on.''