Big-time rockers and Average Joes joined for a workshop and jam session at the Grand Theatre on Sunday.

Young and old strummed their guitars to Joni Mitchell's iconic Big Yellow Taxi alongside award-winning singer-songwriter Emm Gryner, one of the stars in the Grand's upcoming play inspired by Mitchell's music. Some came to the London theatre just to listen, while others - from beginners still mastering chords to grizzled guitarists - came to play, tapping their feet and nodding their heads to the music.

Paul Fujimoto-Pihl was with his wife and young son, Kai, to listen to the music.

"He really likes playing the guitar," said Fujimoto-Pihl, adding his three-and-a-half year-old son doesn't listen to Joni Mitchell yet but, "he will."

Guitar head to shoulder, the approximately 100 music lovers sat on the red velvet seats in the theatre to get a glimpse into the production running from Oct. 18 to Nov. 5, Joni Mitchell: River.

Yvette Laforet-Fliesser, 65, attended, guitar in hand, because she had tickets to the play and wanted to hear more about it.

"We used to sing Joni Mitchell all the time in the '60s," she said of the famed Canadian musician. "Her music is timeless."

Even a few high-schoolers showed up to listen to an artist old enough to be their grandmother.

"I love music and I thought it would be a cool event to play alongside other people," said 17-year-old Shreyas Shah.

The event also brought out some local musicians like Murray Snelgrove, 58.

"It's nice to sort of absorb stuff from the actors and musicians," he said, adding that he'd been singing a Joni Mitchell song in his show for 20 years.

"I would love to hear them play my guitar," he said. "It's a big rush."