Bosses at Welsh organisation Llamau left paper and pens in the dressing rooms of stars performing in Cardiff, Wales and asked them to draw an image of their home.
As well as Costello and Osmond, singer Susan Boyle, rockers The Killers and comic Eddie Izzard took part in the initiative. The images will go up for sale at an auction in the city on Tuesday night (03Jun14).
Hugh Russell, fundraising coordinator, says, "It started as an idea two and a half years ago and we've been collecting them ever since.
"Bags with paper and pens were left in dressing rooms in places like the (Cardiff-based venue) Motorpoint Arena and we hoped celebrities might have some spare time before their shows to help us.
"Many of them did leave us sketches - although some are obviously better comedians than artists."