Urban artist Geoff Filmer led the workshop on January 16, and it took the group of four seven hours to complete the three metre by eight metre artwork.

The finished product, which now adorns the Ashley Drive underpass near the Richardson shops, features 101 faces of the iconic singer who passed away on January 10.

"He's one of those artist who's had an influence on so many other artists, and that's why I thought this was great," said Filmer.

"We played some Ziggy Stardust and other David Bowie music while we worked."

Filmer's creative works are scattered around Canberra, including the painted flock of gang-gang birds in Bunda Street, and he also co-ordinated the street artists who decorated Tocumwal Lane in Civic.

He runs the workshops for all ages and abilities and said growing up with dyslexia is something that particularly drives him to help others.

"Going to school with a learning disability, so often you don't get a lot of wins, you don't get a lot of positive reinforcement," he said.

"Whereas through art you can, no matter how good your writing skills are. It's a brilliant way of breaking down those barriers."

The workshop's participants included 13-year-old Kiana Kerr, who despite her own dyslexia is a budding artist and creative writer.

Filmer said the group was able to create the masterpiece thanks to the ACT government's legal graffiti walls program.

"We have this amazing system for young artists. [The government has] designated a number of spaces, one in just about every suburb around Canberra, so that the people can go and paint," he said.

"So the reason we have a really strong and diverse street art community in Canberra is because we were able to go down on Saturday, and we painted a big wall that people can now go and enjoy.

"It allows complete amateurs to have a go and develop their skills as well as people that are practicing to do really good things."