Boss Brian Kerr named the Spurs trio in his team announced earlier today.
Gary gets his chance again after missing Ireland's last outing - the disappointing defeat at Switzerland last month that saw them bow out of the European Championships.
He starts up front alongside Robbie and they are likely to find another team-mate in their way with goalkeeper Lars Hirschfeld in the Canada squad and expected to start at Lansdowne Road.
The game is on Sky Sports 1 tonight, kick-off 7.30pm.
Meanwhile, Helder Postiga will hope to fire Portugal into the European Under-21 Championship Finals - but they face an uphill task against France in the second leg of their play-off tonight.
Portugal trail 2-1 from their home leg in Guimaraes on Saturday and tackle a French side unbeaten in 15 matches and yet to concede a home goal in the competition.
Stephen Carr, Robbie Keane and Gary Doherty all start for Ireland in tonight's friendly against Canada.