Billu is a family comedy-drama about Billu (Irrfan Khan), a poor barber who once told his children that the superstar Sahir Khan (Shah Rukh Khan) is his childhood friend. Billu’s life changes when Sahir Khan comes to his village for a film shooting. The entire village starts calling Billu their friend and showers him with favours in the hope of getting the chance to meet the superstar. Even after a number of attempts to arrange the meeting, Billu fails. Now everyone, including his family, starts doubting his character and accuses him of lying. Is Billu really friends with a superstar or a liar?