Cher says she is not a diva, Julia Roberts reveals the original dark side of Pretty Woman, Tom Hanks enthuses about moonwalking and Timothée Chalamet reveals how proud he is of Wonka.

Cher, talking about her new album and asked if she listens to her own music, she says, "Not really. I listened to it until I was sure it was right, but I am not a huge Cher fan!"

Asked why she hasn't done a Christmas album before, she says, "I didn't want to. When I did say yes, I wanted to do it myself in my own house. I picked songs l like, and I hate to say it myself, but it is good!"

Talking about her upcoming biopic, and asked who will be playing her in the film, she says, "It is the hardest thing. I have lived too long and done so much, it is very hard to cast, and we haven't even finished the script." Adding, "I will do all the music myself because I don't like imitation."

Asked about spending time in England, she says, "We [Sonny & Cher] actually got famous here. America hated us so we sold everything and came here. When an old lady asked for my autograph, it was like heaven. People really liked us. We got famous and when we went home everyone thought we were English!"

On her love of performing, and asked if there might be a new tour in the works, she say, "It seems so."

And asked if she is a diva, she says, "Don't be ridiculous, I am the least diva-like person. That (behaviour) does not make sense to me."

Julia Roberts, making her first appearance on a UK chat show, and talking about her new film Leave The World Behind, says, "I was sent the book by the director who told me I would love it and to read it as fast as I can, but I just couldn't because it was scaring me and as soon as it got dark, I had to get away from it. The film is spooky and frightening but so good."

Talking about Barack and Michelle Obama's involvement in the film, she says, "They are brilliant people and great human beings who have made the world a better place so when they said they were interested in collaborating on the film through their production company I was very excited."

Revealing Pretty Woman's original title and premise, she says, "It was going to be a much darker film called $3,000 (the price for Vivian to spend the night with Edward). Vivian was a drug addict and the movie ended with him leaving her in a side street, throwing the money at her, and driving away. I got that part in that movie and felt really proud, but when the production company folded and the film disappeared I was crushed. But then Disney picked it up, which seemed so unlikely, and made it funny."

Tom Hanks, talking about his epic London installation The Moonwalkers, says, "It is amazing - there is no CGI, and every picture has been taken with a camera by a human being. It is an extraordinary story, and you will come out feeling like you have walked on the moon."

Revealing that his love of space stretches back to his childhood, he says, "We had a doughboy swimming pool when I was a kid. I had a cheap mask, a brick in the back of my swimsuit that would hold me down at the bottom, and I would breathe through a hose for 10 minutes so I could feel like I was space walking."

Asked if he is tempted to go into space, he says, "I don't need to go up for five minutes and up-chuck before we come back down."

Talking about making Apollo 13 and meeting Jim Lovell, he says, "Kevin Bacon, Bill Paxton and I were recreating the serious moment right after 'Houston we have a problem,' and were going up and down on grips making us look weightless. We looked ridiculous and when I looked down there was Jim looking up at us. I have never felt more stupid in my life."

Doing a science experiment, Tom illustrates the force of gravity on Earth compared with what happens on the moon.

Timothée Chalamet, talking about the new Charlie and the Chocolate Factory prequel Wonka, says, "I am proud of all the films I have done but this is my favourite. It is the most fun I've had working on anything ever. It is sweet and good and will fill you with joy."

And on working in in the UK, he says, "We shot the film in London so, after spending five months here I feel like an honorary Brit - it was joyous."

Asked how, at such a young age, he has been able to pick hit after hit to act in, he says, "I just try to work with great directors."

Cher performs her current single DJ Play A Christmas Song live in the studio.