The rumored new couple stepped out together in Montréal recently, and a source tells PEOPLE they're "interested in each other"

Justin Trudeau was spotted in the crowd at Katy Perry’s concert in Montreal, days after duo dined together in the city. The appearance continues to fuel speculation about a possible relationship between the former prime minister and U.S. pop star, who had dinner at a Plateau restaurant on Monday.

The rumour mill is in overdrive this week as former prime minister Justin Trudeau was spotted dining out with pop star Katy Perry in Montreal — two nights before showing up at her concert there. It's unclear whether the encounters were friendly or romantic,