TORONTO — Former Ontario education minister Gerard Kennedy will formally enter the Liberal leadership race on Thursday.

Sources tell The Canadian Press that Kennedy will declare his candidacy at a noon news conference in Ottawa.

Kennedy, 45, quit Ontario's Liberal cabinet earlier this month to prepare for his leadership bid, but did not officially announce his candidacy at that time.

The federal Liberals won't pick their new leader to replace former prime minister Paul Martin until December, but already the field of candidates is getting crowded.

Former Ontario NDP premier Bob Rae announced Monday that he's running, joining Liberal MPs Michael Ignatieff and Carolyn Bennett, and former Nova Scotia Conservative MP Scott Brison.

Others who have already entered the Liberal race include Joe Volpe, Stephane Dion, Maurizio Bevilacqua and Martha Hall Findlay.

Former hockey star and current MP Ken Dryden is expected to announce his bid on Friday.