Sting, Peter Gabriel at peace in Quebec music festival

So who's bigger, Peter Gabriel or Sting? In a business full of towering egos, the two rockers seamlessly shared a stage as they opened Quebec City's sprawling summer music festival.

The two English artists -- who were born 18 months apart and, in different ways, trailblazed fusion elements in pop music -- essentially turned into a duo as they politely alternated between each other's hits.

Accompanied by a dozen backup musicians on what the festival calls North America's largest self-supporting stage, the pair played for an estimated 75,000 people Thursday night on the wind-swept Plains of Abraham, a former battlefield in the heart of the historic city.

Sting and Gabriel, the former frontmen respectively of The Police and Genesis, are not strangers to each other, having toured together in the late 1980s to benefit Amnesty International.

The human rights focus was still on the minds of the artists, who are spending the summer across Canada and the United States on what they call the "Rock Paper Scissors" tour.

Gabriel, who repeatedly addressed the audience in hesitant French as he read a text from a clipboard, dedicated his song "Love Can Heal" to Jo Cox, the pro-European British lawmaker who was assassinated on June 16 before the country's vote to leave the European Union.

The singer had befriended Cox through human rights advocates before the Labour Party politician's election to parliament. Gabriel said shortly after her death that Britain had been "robbed of a potential leader."

Gabriel, sporting white stubble at age 66, has been a pioneer in championing music from the developing world but for his tour has focused on his pop solo hits, albeit with an infusion of Sting's influence.

Swedish singer Jennie Abrahamson teamed up with Gabriel for the inspirational "Don't Give Up," originally a duet with Kate Bush, in a performance so emotionally resonant the vocalists embraced with seeming spontaneity.

Sting was the more experimental of the two in concert, adding a bluesy touch to the Police hit "Roxanne" which he transitioned into the Bill Withers classic "Ain't No Sunshine."

He brought a cheerier rock feel to "Every Breath You Take" -- the final song until the pair closed with Gabriel's "Sledgehammer."

- Giant but inexpensive festival -

The summer festival, known in French as the Festival d'ete de Quebec, runs until July 17 with other headliners set to include California funk rockers Red Hot Chili Peppers, veteran British pop chart-toppers Duran Duran, West Coast rap great Ice Cube and the adrenaline-charged German metalheads Rammstein.

Other performers on the opening night included the introspective Swedish trip-hop singer Jay-Jay Johanson, Senegalese-born Quebecois singer Karim Ouellet and Australian jazz bass innovator Tal Wilkenfeld, who performed an energetic, stripped-down cover of The Smiths' "How Soon is Now?"

The annual event, which was founded in 1968 when the acts included the cult classic psychedelic band Love, comes as the festival industry grows rapidly around North America.

Organizers estimate that the Festival d'ete de Quebec, which is self-sustaining, generates more than CAN $25 million ($19 million) for the local economy.

More than half of the audience is local and tickets for the full 11-day event start at CAN $90 ($69), far lower than major global festivals such as Coachella and Glastonbury.

In a new move, the festival has started more expensive VIP tickets with assigned seating.

The festival also boasts of being carbon neutral, with organizers encouraging public transportation and recycling and investing in offsets to balance the climate impact of the artists' travel.