Sam Claflin feels inspired by Shailene Woodley.

The 32-year-old actor stars alongside Shailene in the new romantic drama 'Adrift', and Sam has admitted he finds Shailene's activism work to be uplifting.

Speaking about his co-star - who was previously given a year of unsupervised probation for protesting against the construction of the Dakota Access Pipeline - Sam explained: ''There's something so inspiring to me especially because Shailene is younger than I am, I generally find myself looking up to her in many, many ways.

''I think that the fact that she stands up for what she believes in, in more than a lot of people our age, is incredible.''

Meanwhile, Shailene has revealed that there's much more to her activism than simply standing on the picket line in front of photographers.

The 26-year-old actress - who appeared in 'The Fault in Our Stars' in 2014 - has insisted she's passionate about environmental issues and hasn't simply involved herself with certain causes because it's a ''sexy'' thing to do.

Shailene told Yahoo Movies: ''It's sexy to go to a protest, it's sexy to tweet something, it's cool, it feels good to sign a petition but it's not hard.

''What's hard is being uncomfortable and teaching kids things that are different to what the system teaches us, and what society has for so long has taught us, so I think that's where our focus needs to be.''