Megastar Amitabh Bachchan was thrilled when he spotted Hollywood superstar Robert De Niro in attendance at a panel discussion at the ongoing THiNK 2013, a thought provoking fest, here. Bachchan was one of the speakers.

The 71-year-old took to Twitter to share his excitement.

"Just finished my conversation at THiNK...exciting and exhilarating...and in the audience, Mr. Robert De Niro! Stumped for words," Big B posted on the microblogging site Friday.

The third edition of the annual festival, THiNK 2013 is hosting a series of panel discussions which will bring together eminent names from different walks of life- politics, technology, science, literature, medicine, environment, pop culture, business, media, religion, sport and cinema.

The festival, which started Friday, will conclude Sunday.