Who could bring together Andrew and Julian Lloyd Webber, Helena Bonham Carter, Jeremy Irons, Clive James, Elaine Paige and Bonnie Langford to appear on the same stage?
The answer is the late singing coach to the stars Ian Adam, whose life and work is to be celebrated on Sunday in a gala performance in London's West End.
I'd Like To Teach The World To Sing, at the Theatre Royal, will raise money for the newly created Ian Adam Memorial Fund, "Singing for Breathing", to help patients with respiratory problems at the Royal Brompton Hospital, where Adam, who died last May, was treated. The show will tell the story of Adam's life from his boyhood in Scotland to becoming the most famous vocal coach in musical theatre.
Andrew and Julian Lloyd Webber will be playing together in public for only the second time, doing Andrew's "Pie Jesu". Andrew has loaned the theatre, part of his Really Useful Group, for the occasion.
Adam's last project was working with Bonham Carter to prepare her for her singing role in Sweeney Todd, which was directed by her husband, Tim Burton. She will introduce scenes from the film on the night.
Paige will sing the classic Andrew Lloyd Webber song "Memory" from Cats, Bonnie Langford will sing "Tone Deaf" and the actress Siâ* Philips will sing the Rodgers and Hart number "Bewitched, Bothered and Bewildered". Rod Argent and Colin Blunstone of The Zombies are reuniting to sing "She's Not There", while Sally Ann Howes returns to the West End stage for the first time in 15 years to sing "Send In The Clowns" by Stephen Sondheim.
Jeremy Irons, Clive James, Edward Fox, Susan Hampshire and Helen Lederer will also perform numbers, while Anthony Andrews and Gloria Hunniford will narrate.
The event is being produced by Peter French, who will sing "If Only We Have Love" and "In Between Goodbyes", and is being directed by Gillian Lynne, who worked on The Phantom of the Opera with Adam.
Adam was the vocal coach who taught Michael Crawford and Sarah Brightman for Phantom. French said: "When Phantom catapulted to huge success, it launched Ian as well. Everybody on the planet wanted lessons with Ian."
The singers Sting, Lulu, Boy George and Michael Ball were taught by Adam, but his pupils also included the Duchess of York, the broadcaster Clive James, and the actors Robin Williams, Billy Connolly, Pamela Stephenson and Sean Connery.
French came up with the idea after delivering the address at Adam's funeral and looking out over those gathered to see "200 of the biggest stars of British film and television sitting in front of me... Every single one of them was there because they loved this man. He made every student believe they could do it, no matter what it was."
Lynne said: "What I've tried to make is not just a concert, but a show, which I've put together from my knowledge of Ian and the theatre. It starts with the full cast doing Ian's breathing exercises. It starts mystically and becomes outrageously funny."