The production announced the Glee star will take over the role Sept. 6.
"A dream come true is an understatement," Michele wrote on Instagram Monday. "I'm so incredibly honored to join this amazing cast and production and return to the stage playing Fanny Brice on Broadway."
Feldstein announced Sunday she would be leaving earlier than expected after production "decided to take the show in a different direction."
Funny Girl, which follows Brice on her improbable rise to fame as a vaudeville star, first opened in 1964 starring Barbra Streisand. The show's revival debuted April 24 at the August Wilson Theatre in New York to lackluster reviews.
Feldstein will depart the Broadway production July 31, two months before she was scheduled to end her run on Sept. 25.
Understudy Julie Benko will play the title role until Michele officially takes over in September.
Like art imitating life, Michele's character on Glee once aspired to play the lead role in Broadway's Funny Girl in a fictional revival, where Michele performed "Don't Rain on My Parade."
Jane Lynch, who starred with Michele in Glee and played Mrs. Brice with Feldstein on Broadway, will depart the production in September. She will be replaced by Tony nominee Tovah Feldshuh.