MONTREAL -- Montreal MP Justin Trudeau made his Liberal leadership bid official Tuesday, acknowledging his notoriety will "put some people in the bleachers" but won't guarantee a return to past glory.

The 40-year-old made the announcement 44 years after his father, Pierre Elliott Trudeau, ascended to the head of the party and was elected prime minister within months.

The younger Trudeau told a boisterous rally of 500 supporters that the third party in Parliament will have a lot of work ahead if it hopes to leapfrog the NDP and the governing Conservatives.

"My candidacy may shine a few extra lights upon us," he said in a community-centre auditorium, alluding to his last name.

"It may put some people in the bleachers to watch. But what we do with that opportunity is up to us."

The Liberals have been in a prolonged slump since the mid 2000s, battered by the sponsorship scandal and a divisive power struggle between Jean Chretien and his successor, Paul Martin.

Meanwhile, the NDP stormed to official Opposition status in the 2011 election, further decimating the Grits.

Justin Trudeau, first elected in 2008, said the party has learned from past mistakes and should no longer assume it has a monopoly on Canadian values.

"I've too often heard it said in Liberal circles that the Liberal Party created Canada. This, my friends, is wrong," he said.

"Canada created the Liberal Party."

His 20-minute speech contained little in the way of specifics, though he did emphasize the importance of a strong and growing middle class.

The crowd included his wife Sophie Gregoire and their two young children, as well as a mix of young party members and old allies of Pierre Trudeau, who died in 2000.

Among the supporters was Gilles Coulombe, who worked on the elder Trudeau's 1968 campaign in Montreal at the height of Trudeaumania.

While Justin Trudeau played down his family name, Coulombe said it will be an asset.

"I thought I was hearing his father, a bit at the beginning (of the speech)," said Coulombe, who attended the same Montreal private school as Pierre Trudeau.

Despite his excitement, the veteran organizer said there's too much at stake for the Liberals to crown the younger Trudeau as party leader.

"I hope others come forward so that we can have a debate of ideas," Coulombe said.

There are three other relatively unknown candidates in the race, including lawyer Deborah Coyne, who had a daughter with Pierre Trudeau.

Higher-profile hopefuls could announce their candidacies, including Montreal MP Marc Garneau, Canada's first man in space.

The winner will be announced April 14 in Ottawa.