<p>Avatar: The Way of Water stars Zoe Saldana and Sam Worthington knew they were signing up to be 'guinea pigs' again with the sequel, but they relished the technical challenge.</p><p>The stars reprise their roles as Na'vi warrior Neytiri and Jake Sully — a human who now lives permanently in the form of his blue-hued avatar.</p><p>Avatar: The Way of Water is in cinemas and IMAX from 16 December.</p>
