Massey, who was also seen on Broadway in Next to Normal, Xanadu and Wicked, will play Kevin Bicks, one of the most successful singer-songwriters in Nashville who is openly gay.
His television credits include "The Good Wife," "Inside Amy Schumer" and "Hart Of Dixie."
"Nashville" airs on ABC Wednesday nights at 10 PM ET. Visit ABC.Go.com/Shows/Nashville.