Dev Patel stars in one of the most unusual sci-fi movies of recent years, 'Chappie', in which he plays a celebrated engineer and inventor of a robotic police force. However, communicating with a robot as opposed to another actor was always going to bring its challenges.

Dev Patel in 'Chappie'
Dev Patel stars alongside Sharlto Copley in 'Chappie'

He's probably best known for starring in the Oscar winning Eastern drama 'Slumdog Millionaire', but Dev Patel is no stranger to the sci-fi fantasy genre. In 2010, he appeared in M. Night Shyamalan's 'The Last Airbender', but rather than having to weave around various special effects, this time he was expected to enact scenes with an inanimate object.

Watch the trailer for 'Chappie' here: 

'For me, it was really important to understand Chappie the co-star', he explains. 'It was a really big deal because a lot of the script is me talking to this robot and I obviously know how Sharlto [Copley - the voice of Chappie] is going to look but how is this robot going to express itself? How's it going to emote?' With these questions in mind, Patel had little to bounce off in terms of his own acting style. 'It is the namesake of the film and the heart of our movie', he continued. 'I saw some sketches and he's got these big expressive ears and the face has all these emoticons that can come on it and it was just so original.'

More: Read our review of 'Chappie'

The challenges were worth it, however; Patel was thrilled to learn that he was director Neill Blomkamp's first choice to play robotics genius Deon. 'I got sent this iPad that felt like it was going to explode or something', he recalls. 'It had some of his visual inspirations and stuff, some of the cool robots and some of the sketches, and the script was just so inspired.'

More: Neill Blomkamp mixes politics with action in 'Chappie'

Patel stars alongside Sharlto Copley, South African alternative rap duo Die Antwoord (who play fictionalized versions of themselves), Hugh Jackman and Sigourney Weaver.