The former Liberal prime minister also proactively shored up what could be seen as a weakness in Trudeau's campaign: the sense that it's too soon for the young father to reach for the top job.
"He's been elected twice so far," Chrétien pointed out. "It's one more time than his father [Pierre Trudeau] when he became the [Liberal] leader."
"[Stephen] Harper had been elected once only when he became the leader. He had no experience. He was younger than Trudeau," Chrétien added. "Joe Clark the same thing. [David] Cameron in England, the same thing."
"Only me had a lot of experience to become prime minister," he said, laughing. "[Pierre] Trudeau was elected once and he became Prime Minister. I had to wait 30 years of hard work to get the job."
Chrétien served as a cabinet minister under former prime minister Pierre Trudeau.
It's not the first time the veteran politician has spoken favourably about the younger Trudeau, telling host Evan Solomon on CBC Radio's The House in June that the two Trudeaus are "definitely different," but that Justin Trudeau "has proven himself in some way."
"You know, rather than run in a safe seat, he had to run in a difficult seat," Chrétien said in June of Justin Trudeau's Papineau riding in Montreal. "He won and defeated the Bloc, and he's the only one who increased his majority."
Chrétien is not expected to endorse any particular leadership candidate outright, as is the tradition for former leaders of the party.
France Chrétien Desmarais, Chrétien's daughter, became a member of the Order of Canada at a ceremony in Ottawa on Friday. The citation lauded her community involvement and philanthropy.
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