Cariou, who earned a Tony Award for originating the title role in Sweeney Todd and starred as Frederik in the original production of A Little Night Music, will take part in the added 7 PM concert.
Sondheim Unplugged, which has played its weekly engagement at the Beechman since July 5, was originally scheduled to conclude July 26. Kurt Peterson (Follies) recently appeared in an Aug. 2 encore concert.
Each concert has featured an actor who originated a role in a Sondheim musical. Previous guests included Sarah Rice (Johanna in Sweeney Todd), Danielle Ferland (Louise in Sunday in the Park…, Little Red in Into the Woods), Pamela Myers (Marta in Company) and Annie Golden (Lynette "Squeaky" Fromme in Assassins).
Regular performers for Sondheim Unplugged are Carey Anderson, Lisa Asher, Christina Bianco, David Brian Colbert, Harris Doran, Natalie Douglas, Michelle Dowdy, Barbara Fasano, Terese Genecco, Eric Michael Gillett, Larry Hamilton, Joe Iconis, David Gurland, Hunter Ryan Herdlicka, Trent Armand Kendall, Audrey Lavine, Lorinda Lisitza, Karen Mack, Rob Maitner, Cindy Marchionda, Liz McCartney, Susie Mosher, Mark Nadler, Karen Oberlin, Miles Phillips, Shaynee Rainbolt, Leenya Rideout, Jana Robbins, Becca Johnson Southworth, Trevor Southworth, Elizabeth Stanley, Katie Thompson, Will Trice, Jonathan Whitton and Lennie Watts.
There is a $20 cover and a $15 food and beverage minimum. Phone (212) 695-6909 for reservations. The Laurie Beechman Theatre is located within The West Bank Cafe at 407 West 42nd St.