We didn't exactly see this coming.

On April 29, Fringe will make like its Fox counterpart Glee and air a music-based episode. It will be titled "Overture."

“Oh, it’s gonna be a blast,” Lance Reddick told TV Guide Magazine. “It’s basically Walter telling a bedtime story to Olivia’s niece and so it has these extreme versions of [the cast].”

Among the developments ahead on the unique installment: Broyles will play the piano, Astrid will perform a song from “A Chorus Line,” and Olivia will vamp it up as a private eye... who gets serenaded.

“I sing a song to Olivia, which is certainly confusing,” said Blair Brown, who plays Nina Sharp.

This is an episode we most certainly have to see.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.