"Mr Bachchan is an iconic figure and a brilliant quiz show host. He has helped in a great way in taking quizzing into the dining rooms and making quizzing a game show for the whole family," O'Brien told PTI.
He also thinks that the art has changed a lot on the small screen over the years.
"In the early days quizzing was the hobby of intellectuals. Today, quizzing is more about self-improvement.
Today, it is not just about absorbing information, but about imbibing the knowledge and realising how to apply it," he said.
O'Brien is now back with a new season of Bournvita Quiz Contest (BQC) as a host.
"I wouldn't call it a comeback as such; BQC has always been around. We were on air on Colors channel in 2011 and 2012 as well," he said.
BQC started out as a live quiz show in 1972, then as a radio show in 1973 before it debuted on the television. It is completing its 40 years.
"Even after 21 years, every question is vetted through me.
I am still very hands on," O`Brien said.
But otherwise, he does not follow TV much. "I mostly follow news channels and, of course, sports when India is playing. I am a great Rajesh Khanna fan. So whenever there is an old film of him playing on any channel, I try my best to watch," he said.