He was an unannounced special guest for the Power Morphicon in August 2012.

He was an unannounced guest at Power Morphicon in June 2007.

And not too long ago an unannounced guest, a peregrine falcon, swooped through for a visit.

For her annual birthday shows, she's usually joined by unannounced guests.

The balmy weather seemed to drop in like an unannounced guest.

"We had a consultant as an unannounced guest at a business conference," says an investment banker with a major Manhattan-based brokerage firm.

Along with the impromptu jam sessions, unannounced guests often show up.

Buddy Tate, an unannounced guest, sat in with the rhythm section.

And now you have brought death here with you, like an unannounced guest.

There will be an unannounced special guest.