Liberal Premier Kathleen Wynne joined Adam Vaughan to rally his supporters in the riding of Trinity-Spadina on Saturday, touting what she called the former Toronto councillor's track record as a "city builder."
Just over two weeks ago Wynne scored a convincing victory in Ontario's election giving the Liberals a majority government.
The NDP brought in some big-league wattage of its own, as leader Thomas Mulcair made another of what has been many trips to the bustling downtown riding with candidate Joe Cressy.
The New Democrats are looking to hang on to the seat, which was vacated when Olivia Chow stepped down to enter Toronto's mayoral race.
Mulcair says that if voters in a riding known for sending left-leaning politicians to office at all levels of government want to elect a progressive party then "that's the NDP."
It's one of four byelections set for Monday.