Kudos to Jack Walsh, the Producer and Director of Celebrate Brooklyn and the man responsible for last night’s Prince appearance at the opening event of the Celebrate Brooklyn concert series. 

Prince only appeared for seven minutes singing the closing track ("Get on the Boat") on his new CD. “To have somebody like Prince show up
just makes it all the more special for everyone involved," Walsh told the New York Times.

“I sent an email to
a friend in the concert business,” he said, “and it got forwarded to
the right person. It was on a whim, but the response was immediate.
Somehow it just worked out.”

From the New York Times:

The song’s James Brown groove suited the occasion, and gave Mr.
Parker the chance to recreate his horn arrangement from the album.
Prince sang some upbeat lyrics extolling racial harmony, and took a
fleeting solo on guitar. Then he struck a dramatic pose, tossed his
guitar pick and a white towel into the audience, and strutted off.

The Times article said that Prince’s appearance was a surprise to Maceo Parker, the show’s headliner.  But it seems that someone at the Park Slope Food Coop knew about it before everyone else. Hepcat reports that someone announced over the Park Slope PA system at around 8 p.m. Thursday night: "I have it from a reliable source that Prince is performing at Celebrate Brooklyn tonight."