The singer will join the cast of I Dreamed A Dream when it embarks on an 11-week tour of the UK next March.
Boyle will not be playing herself as that role will be performed by Elaine C Smith, who was announced to be playing Boyle earlier this year.
"I am thrilled to be a part of the musical about my life story and very much looking forward to stepping on stage and performing with the cast," Boyle said.
"It is an honest portrayal of my life and has been a cathartic process to be involved in."
The musical's producer Michael Harrison explained: "Having Susan join the cast to perform the finale of her musical is amazing for both ourselves and audiences across the UK and Ireland."
Smith, who is currently starring in the West End show Calendar Girls, added: "There's a lot of pressure to get it accurate and to honour Susan's life story but to do it in a way that is funny, moving and magical and, as the writers, producers and performers, we're doing our best to achieve that."
I Dreamed A Dream will focus on the singer's rise to fame, starting in her hometown of West Lothian and building up to her sensational worldwide success following the airing of her Britain's Got Talent audition.
Meanwhile, Boyle is currently preparing to release her third studio album Someone To Watch Over Me in the US on November 1 and the UK on November 7.
Watch the music video for Susan Boyle's new song 'You Have To Be There' below: