Bachchan, who boarded a flight from Mumbai, wore a white kurta pyajama with a shawl on his shoulder.
The 'Shamitabh' actor entered the 'Tilak' ceremony venue with folded hands and was greeted by the host Mulayam.
Bachchan, 72, took to Twitter in the morning to inform about his journey.
"Took off for Saifai for wedding event... Bad visibility.. Flight diverted to Lucknow... Waiting for clearance... Safety better," Bachchan tweeted.
Prime Minister Narendra Modi also attended the event apart from other prominent political leaders.