Justin Trudeau was sworn in today as the new Liberal MP for the Montreal riding of Papineau. That's the one just next door to his famous father's old riding, Mount Royal.

Julie Van Dusen

At the ceremony Trudeau, 36, the eldest son of the former prime minister, held his own young son, a wriggling toddler, in his arms.

Friends and campaign workers came to celebrate the special event. Trudeau's wife, Sophie Gregoire, and his mother, Margaret Trudeau, sat in the front row beaming proudly.

Margaret Trudeau pointed out that her son is not only following his father's path into politics but his grandfather's as well. Her father was James Sinclair a Liberal MP and minister of fisheries under then prime minister Louis St. Laurent.

"I'm so proud of Justin. I hope he will inspire other young people to get into politics, too," she said.

Asked whether she expected him to throw his hat into the leadership ring one day, she smiled, "I'm not a psychic. "

The young Trudeau boys often went to Parliament Hill with their father when he was still in office and Margaret Trudeau was asked to share some of her stories about Justin from that time.

Only a mother could tell this one: "I'm running down this corridor with breasts leaking, with brand new Justin having had a big dinner in the chambers and trying to get to him. I've had too many stories, too many stories."

Any advice for her son? " Are you kidding? " she said, "as if he'd listen to mommy." But then she went on to add that "manners is my part of it. Just make sure you're polite."

— Julie Van Dusen