Broadway newcomers Christopher Shyer and Ben Livingston will join the cast of Mamma Mia! at Broadway's Winter Garden Theatre on September 26 as Sam Carmichael and Harry Bright, respectively.

The Ontario-born Shyer has appeared in the Canadian premieres of Les Miserables, Miss Saigon, The Phantom of the Opera and Sunset Boulevard and played John Wilkes Booth in Canada Stage's production of Assassins. Other theater credits include Going Down Swingin' NYMF, The Good Life NOHO Arts Centre, Los Angeles premiere, Night of the Iguana Playwrights Theater Center, El Salvador East Cultural Center and the title role in Dracula: A Chamber Musical Neptune Theater.

Livingston's extensive West Coast theater credits include Man From Nebraska, Arcadia, Hay Fever South Coast Repertory, Gross Indecency Mark Taper Forum, Measure for Measure, A Midsummer Night's Dream Ahmanson, Love's Labour's Lost, Merry Wives of Windsor Old Globe, Man and Superman California Shakespeare Theater, Dr. Faustus, Macbeth, Ghosts Utah Shakespeare Festival, Noises Off San Jose Repertory, Pasadena Playhouse, The Merchant of Venice and Julius Caesar Oregon Shakespeare Festival.

The Broadway cast of Mamma Mia! includes Carolee Carmello as Donna Sheridan, Carey Anderson as Sophie Sheridan, Judy McLane as Tanya, Gina Ferrall as Rosie, Andy Kelso as Sky and Pearce Bunting as Bill Austin.

A big-screen version of the hit musical is currently being filmed with Meryl Streep as Donna, Amanda Seyfried as Sophie, Pierce Brosnan as Sam, Colin Firth as Harry, Stellan Skarsgard as Bill, Julie Walters as Rosie, Christine Baranski as Tanya and Dominic Cooper as Sky.