After the Obamas issued a challenge on April 29th, closely followed by Prince Harry and the Queen who responded a few days later, it was now host nation Canada's turn to wage war via social media over the Invictus Games, which is being held in May in Toronto.

In the amusing video, Canada's Prime Minister Justin Trudeau can be seen warning Barack and Michelle Obama, Prince Harry and Queen Elizabeth II, to "bring it," before dropping to his knees to do a few push ups with a couple of the Invictus Games team members.

"Oh hey, I just thought I'd show our friends in the US and the UK this is how Canada brings it. Your majesty, Prince Harry, President and Mrs Obama ... boom! Orlando, Invictus Games. Canada's ready."

Prince Harry met with Trudeau earlier in the day to promote the Invictus Games, which will be held in the Canadian city from May 8th through the 12th. The Invictus Games are an international Paralympic-style multi-sport event created by Prince Harry, in which wounded, injured or sick armed services personnel and their associated veterans take part in sports including wheelchair basketball, sitting volleyball and indoor rowing.