John Boyega crashes BBC Radio 1 to play 'Sit Down, Stand Up'—a hilarious phone prank game where he and Greg call unsuspecting people and guess whether they're sitting or standing. Victims include comedian Alan Carr (sitting, knitting), John's mate Lavelle (sitting, not moving as expected), John's dad (screening the call from the toilet), and a mortified BBC executive. Chaos, laughter, and brutal truth-telling ensue.