The awards, hosted by the Dead’s Phil Lesh, will be held April 26 at The Theater at Madison Square Garden. Other performers will include Les Claypool, Yonder Mountain String Band and Keller Williams.

The Jammys, determined by fans, honor the best music to come out of the improvisational music scene. Fans can determine this year’s winners – including best album, live show and tour – by casting their vote on the Jammys Web site.

While Adams and Hornsby might seem out of place at the Jammys, Peter Shapiro, the event’s executive producer, told said their inclusion is part of the Jammy tradition of tapping a variety of acts.

“The jam band world really includes music from all genres,” said Shapiro, who is producing the event along with Relix magazine and the web site jambands.com. “What we try to do at the Jammys is to celebrate great live music from all genres.”

The event also will honor an act for lifetime achievement; the recipient will be announced later, along with other performers.

“As in past years, we expect a night of a lot of surprises and we’re really excited with our initial lineup,” Shapiro said. “The initial lineup provides a great base for what is going to be an amazing night of great music.”