Megastar Amitabh Bachchan, who turns 70 Thursday, was in for a surprise when the crew of his popular TV show "Kaun Banega Crorepati 6" (KBC) celebrated his birthday with a cake, which had his face made on it.

"Indian Idol 6" winner Vipul Mehta opened the episode with a birthday song made especially for the occasion.

After the shoot got over, Vipul surprised Big B by bringing in a special birthday cake. The customized cake had Big B's face imprinted on it.

Vipul gathered all the contestants and Big B to cut the cake amidst lots of applause and birthday song sung by the contestants.

The episode will be aired Friday on Sony.