On Star World's popular celeb talk-show 'Koffee With Karan', beaming Friday (Jan 7), Karan Johar has pulled off another coup combo. This time it's Amitabh versus Abhishek Bachchan!

In the Bachchan versus Bachchan show there is much good-natured sparring. The two banter about wearing each other's shoes and clothes and have a good-natured laugh over private jokes.

Laughs the senior Bachchan, "Abhishek and I had great fun doing the show. When Karan called us we couldn't say no. Karan is like a son to me and a brother to Abhishek. I'm glad we went. Because we had a whale of a time."

The best part of the whole exercise (besides the shower of gush from female fans and co-stars) was the bantering and bonhomie between the father and son Bachchan.

"I had decided long before I became a father that my son was going to be my best friend. And I'm happy to say I got that. Abhishek is my best friend," says the proud papa.

Over to Abhishek, "Pa has the best sense of humour in the world. He's my worst critic and I'm his best."

You can say that again, Abhishek!

The "Dhoom" dude has no qualms in admitting on Karan Johar's show that "Boom" is the worst film the senior AB has done.

Karan of course is giggling all the way to the bank...or wherever he stashes away the loot that Star gives him each week.

"Have I been given an unheard-of price to host this show? I don't know," Karan pretends to be dismissive when I ask.

"It depends on what you've heard. But seriously every segment is a challenge. And I'm now running out of attractive filmy combos. I'll now move on to celebs from other walks of life.

"Getting the two Bachchans together was a challenge. I wanted them to come across as they're together without the camera. And they have! Amit Uncle and Abhishek are friends in real life."

Senior Bachchan quips, "But please don't expect to see us playing the same roles in 'Bunty Aur Babli'. Abhishek and I are on opposite sides of the law in Shaad Ali's film."