Global music sensation One Direction guest stars in a riotous new episode of iCarly, exclusive to Nickelodeon on Tuesday July 26 at 4:30pm. One Direction's Harry Styles, Zayn Malik, Liam Payne, Louis Tomlinson and Niall Horan play themselves in a music-filled iCarly episode 'iGo One Direction' , with the hit pop band making their acting debut to perform 'What Makes You Beautiful' on iCarly's web show.