Will.i.am talks about sending his songs to Mars;
Miriam Margolyes is overwhelmed by Will.i.am's philanthropy; Greg Davies says it is a fluke he is Welsh; and Adam Lambert talks about being Freddie Mercury.

Will.i.am, revealing he was asked some time ago to carry the Olympic torch, says, "I had to keep it a secret for a while and it was hard for me not to Tweet about it."

Asked about tweeting while carrying the torch, and the controversy it caused, he says, "That's when I was allowed to Tweet about it! When they created the Olympics there wasn't Twitter. The torch is a light and all I was doing was sending the light across the planet."

On donating £500,000 to The Princes Trust he says, "I had so much fun doing The Voice and your country didn't need to accept me the way it did. I just didn't feel taking the money I earned so wanted to use it for some good."

Talking about his strict upbringing he says, "My mom would make me wear suits to school because she said I was going there to learn and not to play. She was really strict growing up but now she is really laid back, my little brother got it easy. There were a lot of words I wasn't allowed to use at home so when she she's in the audience and I'm performing I have to change all the swear words!"

Reluctantly confirming that NASA has asked him to write the first song to be played on Mars, Will.i.am says, "I don't think I can talk about it, but there is a rocket going to Mars, it lands in August and when in lands it will send back a signal to earth and that signal will be the song. This project with NASA is to help inspire kids to get involved in science, technology, engineering and mathematics. My mission is to inspire the youth to care about education."

Clearly hitting it off with the singer and overwhelmed by his good deeds, Miriam Margolyes says to Will.i.am, "You're fabulous! How unexpected that a rapper would do this. I don't have a very positive attitude towards rappers. I don't really know any, you're the first one I've actually talked to."

Miriam reveals she once scared some BBC painters who teased her about her ample bosom, "They were making fun of me and I thought, 'I'm not having that' and I put their great big hands on my great big breasts and they were terrified. The next time I walked down the corridor they were busy painting and didn't say a word!"

Greg Davies says his father desperately wanted him to be Welsh, "When my mother went into agonising labour and there was a hospital just six miles down the road, my father insisted on driving her 48 miles across the Welsh border just in case I turned out to be a Welsh international rugby player and he got an asthmatic comedian."

Adam Lambert performs Never Close Our Eyes live in the studio, before joining Graham for a chat.

Talking about fronting Queen, "Brian and Roger asked me to front the band for a couple of performances and I was gagged. My jaw fell to the ground and I said, 'me? What?' I am honoured. My big goal is not to stray too far from the original, people want to hear these iconic songs and to veer away too far would be sacrilege. I can't hold a candle to Freddie Mercury. He was a god of rock so it's nice to pay tribute."

And on his number one chart success, he says, "It's crazy but it feels amazing. I worked my butt off on it and I can now breathe."

And finally, Graham pulls the lever on Will.i.am and other foolhardy souls brave enough to sit in the red chair.