New Delhi, Sep 26 : Renowned teacher Khan Sir has extended an invitation to Bollywood megastar Amitabh Bachchan to come to Patna, Bihar, and relish the popular dish of the state- Litti Chokha. Khan Sir is a popular Youtuber and teacher, who is well known for his teaching style on social media. His YouTube channel is called Khan GS Research Center and he has an offline academy by the same name. His YouTube channel has 21.6 million subscribers. In the special episode 31 of the quiz based reality show 'Kaun Banega Crorepati' season 15, host Amitabh Bachchan invited Khan Sir and comedian Zakir Khan to the hot seat. Big B said to Zakir: 'How do you feel sitting on the hotseat'? To which the latter replied: 'Sir, it's a childhood dream come true.' Zakir continued saying: 'I'd like to repeatedly tell you that 'Ajooba' is my favourite film. I loved that film.' The actor asked Khan Sir: 'Do you get time to watch our show 'Kaun Banega Crorepati''? Khan Sir said: 'I watch the show whenever I get the time. And whenever we ask children questions, then I also ask them 'should I lock it?'' Big B said: 'It's become a popular dialogue...' For the Rs 3,000 question, the guests were asked an image based question. The question read as: 'Which of these is a traditional accompaniment to 'chokha''? The options were- Image Option A, Image Option B, Image Option C, and Image Option D. They gave the right answer which was Image Option C. Khan Sir said: 'Sir, l'd invite you to come to Patna and we'd serve you Litti Chokha. It's the most popular dish in our region.' The 80-year-old actor said: 'I've been there many times and eaten it too. It's delicious.' Litti is a main course dish that forms a part of Bihari cuisine. 'Kaun Banega Crorepati 15' airs on Sony. /IANS