Bono, left, director Davis Guggenheim and The Edge, right, arrive for the gala screening of the U2 documentary "From the Sky Down" at the Toronto International Film Festival. (Nathan Denette/AP)

Wearing his signature shades, Bono, film director Davis Guggenheim and The Edge attended the premiere. The film follows the band as it return to Berlin to remember recording the 1991 album “Achtung Baby.”

The band’s first doc, 1988’s “Rattle and Hum,” didn’t get the warmest critical reception. Bono told the crowd the foursome are protective of their recording process “because of that old adage, if you knew what went into the sausage, you wouldn’t eat the sausage.”

But Bono can breathe easy. Variety gave their second attempt at a doc a positive review, writing that Guggenheim “takes an enjoyably novel approach to rock stars known for their fine-tuned products.”

“In the terrain of rock bands, implosion or explosion is seemingly inevitable,” the director, whose past works includes the Oscar-winning documentary, “An Inconvenient Truth,” wrote on the band’s Web site. “U2 has defied the gravitational pull towards destruction,  this band has endured and thrived. The movie ... asks the  question why.”

The Irish-born Bono also told reporters he would be in New York on the 10th anniversary of 9/11. “Even if you’re not American, everyone became an American that day,” he told the Associated Press.

More than 300 films will screen at this year’s fest, including Madonna’s “W.E.” and George Clooney’s “The Descendants.”