Riabko succeeds Tony nominee Jonathan Groff in the role of the freethinking catalyst of the hit musical. Groff exited the Broadway company May 18 along with fellow original cast member Lea Michele.

Earlier this week, on May 20, Michele was succeeded by Spring Awakening ensemble member Alexandra Socha in the role of Wendla.

Riabko, whose solo recording "Before I Speak" is currently available on the Columbia Records label, has toured with musicians including Jason Mraz, Maroon 5 and John Mayer.

"I actually saw the musical well before I considered being a part of it and loved it so much," Riabko said in a statement on his official website. "The reason Spring Awakening appeals to me is the reason I think it appeals to every young person.

"I am not that far away from all of the events in the show," he continued. "Not only do I remember those exact issues, but I am kind of living through them at the same time as well." The Spring Awakening company also features Blake Bashoff (Moritz), Skylar Astin (Georg), Lilli Cooper (Martha), Blake Daniel (Ernst), Brian Charles Johnson (Otto), Emma Hunton (Ilse), Phoebe Strole (Anna), Matt Doyle (Hanschen), Remy Zaken (Thea), Christine Estabrook (Adult Women), Glenn Fleshler (Adult Men), Gerard Canonico, Alice Lee, Eryn Murman and Matt Shingledecker.

Based on the 1891 play by Frank Wedekind, Spring Awakening won eight 2007 Tony Awards, including Best Musical. The production features direction by Michael Mayer, choreography by Bill T. Jones, book and lyrics by Steven Sater and a score by Duncan Sheik.

Spring Awakening launches a national tour at San Francisco's Curran Theatre Sept. 4-Oct. 12. Prior to officially hitting the road, Spring Awakening will rock San Diego's Balboa Theatre Aug. 15-31. Casting for the tour will be announced shortly.

Songs featured in the Tony-winning score are "All That's Known," "And Then There Were None," "Blue Wind/Don't Do Sadness," "Left Behind," "Mamma Who Bore Me," "My Junk, "The Bitch of Living," "The Dark I Know Well," "The Guilty Ones," "The Song of Purple Summer," "The Word of Your Body," "Those You've Known," "Totally Fucked," "Touch Me," "Whispering" and "The Mirror-Blue Night."

The musical made its world premiere Off-Broadway at the Atlantic Theater Company in June 2006. Spring Awakening transferred to Broadway the following November, where it continues to play at the Eugene O'Neill Theatre.

For tickets call (212) 239-6200 or visit www.telecharge.com.