Harper channels Judy Garland, Patsy Cline, Edith Piaf, Billie Holliday and Maria Callas in the show which has been described as "spellbinding."
"That's why I need to make sure I get enough rest between performances," she says.
"Singing in a Judy Garland key and then singing as Maria Callas can take a toll on my voice," she says.
Harper collected the best actress award at the United Solo Festival in New York in 2014 with another of Joanna Murray-Smith's one-woman plays Bombshells.
She has been invited back to the New York United Solo Festival this year as an encore performer and will take Songs for Nobodies to 42nd Street in October.
"In my 25-year career, there have been a handful of scripts that have come my way and have felt like a gift. Songs for Nobodies is one of those gifts.
"I love the way the show poignantly explores the uncanny influence that chance encounters, both directly and indirectly, play in our lives," she says
The show includes songs such as Patsy Cline's Crazy, Judy Garland's Come Rain or Come Shine and Edith Piaf's Non, Je Ne Regrette Rien.
Director Ross Gumbley says, "I have been so excited to be on this journey with Ali.
"Seeing the reaction that this exceptional play, performed by a truly gifted performer, draws from an audience is fantastic."
Ali Harper will perform Songs for Nobodies at the Royal Wanganui Opera House on Tuesday, September 4 at 7.30pm.
Tickets can be purchased online at seatadvisor.com or from Royal Wanganui Opera House Booking Office.
