In a dramatic, "dream come true" moment for Sangeeta Ghosh, megastar Amitabh Bachchan went down on his knees with a rose in his hand, and recited a dialogue from his movie "Silsila" for the actress on the set of "Kaun Banega Crorepati".

No, it wasn't real case of "Cheeni Kum" chemistry, but just a demonstration of a romantic proposal that Big B was giving to actor Ruslaan Mumtaz, Sangeeta's co-star in the show "Kehta Hai Dil...Jee Le Zara".

Sangeeta and Ruslaan made a special appearance on the show for its Dussehra special episode, which will be aired Sunday.

When the thespian, who turned 71 earlier this week, asked young Ruslaan as to when will his character finally express his feelings to Sangeeta's character on the show, Ruslaan said: "Sir aapne bol diya hai ab mein jald kar dunga (Now that you have said it, I will do it soon)".

As a test, Big B asked Ruslaan to give a demo of his prospective proposal. He gave Ruslaan a rose, and asked him to go ahead and propose to Sangeeta. But Ruslaan did an unimpressive and immature job.

That is when Big B intervened and said that if this is how a boy will ever propose, the girl will run away. He then took the rose from Ruslaan and went down on his knees and recited a dialogue from the movie "Silsila" and proposed to Sangeeta.

Sangeeta's happiness knew no bounds and she kept blushing through the entire show, said a source.