The incident occurred Monday night during Doordarshan's 'Janmat 2014' programme that was being shot at Tikonia Park.
A debate was taking place between leaders of various political parties. Suddenly a young man drenched in petrol stepped out and set himself on fire.
He then rushed towards Bahujan Samaj Party (BSP) leader Kamruzzama Fauji and embraced him. The man and the BSP leader sustained serious burn injuries.
Police said the youth, Durgesh from Mau district, suffered 95 percent burns while Kamruzzama Fauji sustained 75 percent burns. Both were rushed to the trauma centre in Lucknow, where their condition is stated to be critical.
Both the victims are battling for their lives, a doctor told IANS.
Congress leader Ram Kumar Singh and another leader Chowdhary Hriday Ram Verma also sustained minor burn injuries while trying to save them.
A key of a local hotel has been recovered from the man.
Police have so far not been able to know the reason behind the extreme step.