Bob Geldof wasn't sold on the idea of a Live Aid stage musical, at least not at first.

To paraphrase his colourful words, he thought it was a crappy idea.

Producers had approached him with an early draft of "Just For One Day," their pop-infused stage show about the making of the legendary 1985 benefit concert he helped organize. When he flipped through it, he was unamused.

"I didn't think it was interesting at all," he explained of the musical, which hits Toronto next year.

"The first script was terrible, really terrible. And I just said, there's no way."

For one, he said their book didn't shed light on why the concert took place at all. The effort to raise funds and fight famine in Ethiopia was a multi-venue effort that eclipsed anything like it before.

But the 72-year-old Irish singer-songwriter didn't quash the idea of a Live Aid musical. As the producers persisted, he warmed to the concept, helped by script revisions which found the story's "sense of adventure."

Ahead of Live Aid's 40th anniversary next year, "Just For One Day" rolls into Toronto for its North American premiere, after a sellout run at London's Old Vic.

The show plays at the Ed Mirvish Theatre from Jan. 28 to March 16, 2025.

"Just For One Day," named after a lyric in David Bowie's "Heroes," recounts the ambitious making-of story behind Live Aid, drawing on interviews with the people who were there to create a semi-fictionalized tale.

It centres on Geldof and his charitable aspirations, adding a fabricated romantic subplot and giving him a few musical numbers. Other characters orbit him with their own dramatic stories drawn from real life. Mirvish says the cast will be announced at a later date.

Thirty-seven songs are featured from the likes of Live Aid superstars Bob Dylan, Elton John, U2, Diana Ross, Queen and Madonna, though none appear as characters in the musical.

The show is directed by Luke Sheppard, who brought pop odyssey "& Juliet" to life, and written by John O’Farrell, once the lead writer on the 1980s British satirical puppet series "Spitting Image," which repeatedly skewered Geldof's involvement in charity singles.

Geldof eventually signed off on the project. And he believes in the musical enough to pause gardening at his home in the south of France to explain why he was eventually won over.

"Look, I wouldn't do this if I thought it was (crap), I'd be embarrassed," he added after he dusted off his muddied hands in a video call Monday.

"I thought it was great."

Geldof said it came down to lead producer Jamie Wilson, who was involved in the project from its inception. He begged Geldof to attend an early workshop and witness why he was so excited about the concept.

Eventually, Geldof agreed, and with the Who's Pete Townshend in tow, descended on a giant empty studio space to observe a rough draft performed by a small cast of experienced actors who'd only read the script the night before.

He remembers being ushered to a set of bleachers placed before a group of chairs for the actors, and a four-piece band who performed a setlist narrowed down from hundreds of songs played at Live Aid.

"I was blown away," Geldof said.

"I know this sounds wanky if you're into music but ... the music was insanely good."

He walked out of that preview convinced the Live Aid musical had some hope. Many script revisions followed, leading to its premiere at the Old Vic in February.

"I'm not a big theatre freak, but I've never seen a standing ovation before the intermission," Geldof said.

"So great, I was wrong criticizing it the way I did. It's not my sphere of understanding. But I get it now."

Producers say 10 per cent of all ticket sales from the Toronto performances will be donated to the Band Aid Charitable Trust, which supports organizations fighting poverty and famine.

Geldof admits he finds it jarring to balance conversations about a flashy musical with the realities of ongoing famine in Africa.

Each day, he said, his email box is filled with messages from people tied to the charity which serve as a reminder this crisis has worsened, even if other world events suck up much of the public's attention.

"(The emails) will sound benign and they look neutral, but what they're describing in amongst those words is another horror," he added.

He dismisses critics who suggest that Live Aid failed at its purpose simply because famine has worsened in the region.

"Because of what everyone did," he said, "there are hundreds of thousands, if not millions of people, alive to determine their own life."