"We are going to come clean," Sting told the crowd, "we are gonna go on tour."
By David Willis
BBC News, Los Angeles
It was the announcement Police fans the world over had dreamed of but thought would never come.
The Police, led by Sting, stopped touring together in 1984
Asked a few years ago on American radio whether he could ever conceive of a reunion tour, Sting had replied that such a notion would be "insane".
Fast forward to the gathering at one of the world's most famous rock venues - Whisky A-Go-Go on the Sunset strip - and he was asking fellow members of the band if they recalled the words to Message in a Bottle.
They played four songs, and despite seeming a little rusty on occasions had clearly lost none of the enthusiasm that made them one of the most famous rock bands in the world.
"If you had asked me the day before I made the decision whether we should go back on tour, I would have said you are out of your mind, " Sting said.
"But a light bulb went off and I found myself calling the other two to say 'hey, we should go on tour'."
He added that The Police were a facet of his life which he had spent 25 years running away from. A period in which they sold more than 50 million albums worldwide.
Sting, Stewart Copeland and Andy Summers will kick off their tour in Vancouver
How did it feel for the other members of the band, when Sting made his call?
Andy Summers - at 64 the oldest member of the group - described it as "soulful" moment.
"Finally, after 20 years of dealing with the prospect of a reunion virtually every day, today comes as a huge relief," he told BBC News.
"I really think we stopped too early - people never got enough of us."
One of their most popular songs, Don't Stand So Close to Me, was inspired by the disagreements between the three which ultimately led to them going their separate ways.
Now older and wiser they no longer use fists to settle their differences.
Sting insisted they fought because they cared about the music, not because they hated each other.
A little rusty
"We fought tooth and nail," he said, "but as human being we always liked each other."
They are, by their own admission, a little rusty after more than 20 years apart.
But just the thought of them playing live all over again is enough for fans like Paul Carter, who travelled all the way from Southampton to see them at the Grammys.
"With the rise of Pop Idol, the fat lad down the pub can now be number one and so there's space for a proper band," he said.
"I think The Police's time has come."
The 30th anniversary tour will begin in Vancouver at the end of May and take in North America before moving to Britain in September and Europe the following month.
As they left the stage at the Whisky, drummer Stuart Copeland said: "We'll be back."
He then corrected himself: "We ARE back!"