Independent MP Bruce Hyer says he'ill join the Green party, giving it a second seat in the House of Commons.
Hyer is a former New Democrat who left that party in April 2012 after breaking with party policy and voting to scrap the national long-gun registry.
The Ontario MP was first elected in Thunder Bay-Superior North in 2008 and re-elected in 2011.
Hyer says joining the Greens will allow him to stand up for the interests of his constituents and have the resources of a national party behind him.
Green Leader Elizabeth May says she's thrilled to have Hyer join her.
NDP ethics critic Charlie Angus says Hyer is breaking faith with voters and should resign and run in a byelection.