It took a while, though.
In the meantime Henrichsen, who sings, plays guitar and does a passable Idol impersonation, put together an '80s cover band, Nite Wave. They began playing a series of charity concerts dubbed Billy Idol Aid and raised more than $10,000 for the American Red Cross and Northwest Harvest, which supplies meals to food banks.
But when October 2011 came around, Idol didn't show. Instead, he sent a video, saying he was sorry he couldn't make it — but there was always next year.
Though some friends and family were a bit tired of the project, Henrichsen decided to give it one more year. He had bimonthly chats with Idol's people to update them on his status. Eventually, the Showbox, a Seattle venue that hosted some of the Billy Idol Aid events, made an offer to host the event at its location south of downtown.
Finally, last August, Idol's people called from Japan, where he was touring, and said Idol was in, with his band. Henrichsen says he started screaming and running laps around the mall.
And when 900-plus people showed up for Billy Idol Aid IV, they were treated to an official video announcement from the man himself.
"The people of the world have spoken!" Idol thundered. "The dream will become reality ...."
"It's gonna be pretty much the coolest night ever," says Henrichsen, whose birthday was Monday. "We'll have as much fun as possible before we get to the 9-5 part of my life."