Watch them belt out the hits with their BFF James.
■ Niall revealing he would marry Selena Gomez (!)
■ Harry hitting some impressive high notes.
■ An impromptu in-car music video shoot for fan favourite 'No Control'.
■ An actually quite good rap verse from James Corden.
■ Live renditions of classics like Story of My Life and Best Song Ever.
1D also discuss the good and bad sides of fame, what their plans are for the break and whether or not James should be allowed to join the band.
Fans who attended the initial filming back on December 3, noted that the band also covered the Backstreet Boys "I Want It That Way" so look out for additional footage to potentially surface in the coming weeks.