Jackie Chan and Chris Tucker chatted with ET on the set of 'Rush Hour,' explaining how they blended action and comedy for the 1998 classic. In behindthescenes interviews, the martial arts icon joked about how much his costar improvised while filming. The 'Friday' star recalled teasing him while singing their 'War' duet, calling out Jackie, who also boasts a prolific singing career overseas, for 'trying to sell some albums' off their memorable scene.