OTTAWA -- Justin Trudeau launches his campaign for the federal Liberal leadership Tuesday, determined to prove he's not just the telgenic eldest son of his famous father.

The 40-year-old Montreal MP and prohibitive favourite is to make his long-expected plunge into the contest at an evening rally in his Papineau riding.

The event, expected to be attended by as many as 500 constituents, will showcase Trudeau's undisputed talent for attracting and energizing supporters.

But his team also hopes his speech to the adoring throng will help dispel the biggest knock against Trudeau: that he's all sizzle and no steak.

According to one campaign insider, it will be a "meaty" speech, designed to demonstrate the youthful MP has "a mature and thoughtful perspective on the country." It won't spell out any specific policy pronouncements but it will lay out Trudeau's "values, objectives and methods" of achieving them.

It will include Trudeau's blunt diagnosis of why the once-mighty Liberal party was reduced to rubble in the 2011 election: It lost touch with middle-class Canadians who used to be the party's bulwark.

And he'll offer his prescription for reconnecting with the middle class and rebuilding the party over which his late father, Pierre Trudeau, presided from 1968-84, all but nine months of that time as prime minister.

Trudeau will set out across the country immediately after his launch, hitting Calgary, a Liberal wasteland since his father's hated National Energy Program, and Richmond, B.C., on Wednesday and a rally in Mississauga, Ont., on Thursday, hosted by former MPs Navdeep Bains and Omar Alghabra.

The invitation for Trudeau's Richmond event offers a hint of the policy priorities he intends to champion and the voters he hopes to win back to the Liberal fold: young people and cultural communities.

"For Justin, investing in youth, diversity and the environment are the best ways to ensure our country's long-term prosperity and he is increasingly convinced that the Liberal party is the best vehicle to champion these issues and to create the Canada that the world needs us to be," the invitation says.

While today's launch is intended to showcase Trudeau's appeal among average folk, the presumptive front-runner will have no shortage of support among the party's elite. He is expected to announce a raft of endorsements from Liberal MPs and senators within 10 days.

Trudeau has been in the public eye since he was born on Christmas Day, 1971. As a child, he travelled the country and the world with his famous father, then prime minister.

He was a school teacher before jumping into politics in 2008. He eschewed offers to run in Montreal's Outremont riding -- then considered a safe Liberal seat, now held by NDP Leader Tom Mulcair -- choosing instead to fight a contested nomination in Papineau, once a Bloc Quebecois stronghold and among the poorest ridings in the country.

He defeated a star Bloquiste in 2008 and bucked the NDP tide that swept Quebec in 2011, increasing his margin of victory.

In Liberal circles, he is an undisputed rock star, the party's biggest draw at fundraisers. He boasts more than 150,000 Twitter followers. His already sky-high stock soared last spring when he won a charity boxing match against Conservative Senator Patrick Brazeau.

For all that, Trudeau remains an unknown quantity in many respects. In his various shadow cabinet posts -- youth, amateur sport, immigration -- he's had little to say about the big issues of the day, virtually nothing about the economy.

When he's ventured occasionally into meatier issues, he's invariably created controversy -- criticizing the government's use of the word "barbaric" to describe female genital mutilation, suggesting he'd support Quebec secession if he thought Canadians shared Prime Minister Stephen Harper's values.

His choice of campaign team suggests Trudeau is well aware he needs to demonstrate more depth and substance.

Among his key supporters is Gerald Butts, longtime friend and former head of policy for Ontario Premier Dalton McGuinty, and a raft of key organizers from policy-wonkish Gerard Kennedy's 2006 leadership bid, including campaign director Katie Telford, Bains and Alghabra.

Kennedy himself is still pondering whether he'll take a second run at becoming federal Liberal leader. He insisted Monday he won't be deterred by the fact that his old team seems to have moved, almost en masse, to Trudeau, who endorsed Kennedy in 2006.

"I think Justin has a lot to offer the country," Kennedy said.

But he added: "There've been prohibitive favourites before. Sometimes they've won and sometimes they haven't."

Toronto-based constitutional lawyer Deborah Coyne, the mother of Trudeau's half-sister, has already announced her candidacy, as has Manitoba paramedic Shane Geschiere.

A host of others are considering taking the plunge but may yet be scared off by Trudeau's presumed edge.

Among them are Montreal MP Marc Garneau, Canada's first astronaut, Vancouver MP Joyce Murray, former cabinet minister Martin Cauchon, former MP and leadership candidate Martha Hall Findlay, Ontario government economist Jonathan Mousley, former Ottawa candidate David Bertschi, Toronto lawyer George Takach, and David Merner, former president of the party's B.C. wing.

New Brunswick MP Dominic LeBlanc, a lifelong friend of Trudeau's, and Ottawa MP David McGuinty are also mulling their chances but are not considered likely to take the plunge. Veteran Montreal MP Denis Coderre is pondering whether to run for the Liberal leadership or mayor of Montreal and is thought to be leaning toward the latter.

The contest doesn't officially begin until Nov. 14 and culminates on April 14.