Hamilton-born actor Rick Roberts says Jack Layton's mustache was like a "gift" for him as a performer.

Roberts spent hours in the makeup chair on the set of Jack, a new biopic that recounts Layton's relationship with his wife, his early days in Toronto municipal politics and his emergence onto the national stage — all leading to the NDP's impressive 2011 federal election campaign and his death from cancer just months later.

Each day, artists would slather Roberts' face with gelatin prosthetics — covering his cheeks, chin and earlobes inch by inch until he was a dead ringer for the late federal NDP leader.

But it all came together when that famous mustache was affixed upon his face.

"It's an icon unto itself," Roberts told CBC Hamilton.  "Seriously — if you have someone in an orange shirt hold a piece of paper under their nose, it screams Jack Layton."

'If the film can show Jack as an ordinary person who wanted to make a difference in this world and lived his life to the fullest — if it inspires other people to do the same, it will be worth it."'—Olivia Chow, NDP MP

Roberts has been part of over three dozen film and television productions, but got his start at Hamilton's Westwood Elementary as the lead in The Do Nothing Frog.

"I was very excited for that one," he laughed.

Though he's come a long way from those humble beginnings, Roberts originally didn't think he was the right fit to play Layton. Still, he auditioned on a whim, and got the part.

"After I was cast — that's when the fear set in," Roberts said. He lives in Layton's old riding of Toronto-Danforth, and is "surrounded by people who really like him." That was always in the back of his mind on set, he says.

Alongside the arduous makeup process, Roberts dropped 25 pounds so that he'd more closely resemble Layton as he battled cancer on the campaign trail in 2011. He spent months pouring over YouTube videos of the NDP leader as well as candid home movies provided by his family.

Like most actors when they dive into a new role, Roberts spent a fair bit of time trying to figure out just who Jack Layton was behind closed doors. But he soon realized there was no "other" side of Jack Layton that was kept hidden from public scrutiny, he says.

"His public life really was his life in general," Roberts said.

A large part of the film centres in on Layton's personal life and his relationship with wife Olivia Chow, played by CBC Radio host Sook-Yin Lee.

"Our story was quite typically Canadian," Chow, an NDP MP, told CBC News.

"If the film can show Jack as an ordinary person who wanted to make a difference in this world and lived his life to the fullest — if it inspires other people to do the same, it will be worth it."

Roberts says the film is less a story about a political victory and more an insight into a man many Canadians mourned.

"For me, the political campaign was the highway, but the actual story is the personal story told on that journey," Roberts said.

"He really was the guy that kept people up even when they were down."