Justin Trudeau joined in horsing around with Mr Johnson as the British Prime Minister suggested he take his shirt off and reveal his pecs “to show that we’re tougher than Putin”.
As the sun shone at Schloss Elmau in the Bavarian Alps, where the G7 leaders were meeting, Mr Johnson questioned whether they should keep their suit jackets on.
Mr Trudeau joined in, referring to a “bare-chested horseback ride” – Mr Putin was pictured shirtless riding a horse in 2009.
Mr Johnson then said: “We’ve got to show our pecs.”
It came as the Prime Minister insisted his “golden rule” is to “focus on what we are doing” after revealing he plans to be in office into the 2030s.
He admitted he has not “had time” to reflect on the biggest regret of his premiership so far, but claimed the Government’s achievements have been “remarkable”.
It comes as pressure has been mounting on the Conservative Party leader from across the political divide following the Tories’ stinging by-election defeats in Wakefield and Tiverton and Honiton.
Mr Johnson said during a trip to Rwanda this weekend that he is “thinking actively” about fighting the next two general elections to become the longest-serving post-war leader.
Asked at the G7 summit in Germany on Sunday if his ambitions are delusional, Mr Johnson said: “What I’m saying is this is a Government that is getting on with delivering for the people of this country and we’ve got a huge amount to do.”
He said the “golden rule” is to “focus on what we are doing” – to address the cost of living, the “massive” plan for a stronger economy, and “making sure that the UK continues to offer the kind of leadership around the world that I know our people want”.