From Wikipedia:
Montana is a song composed by Frank Zappa for his 1973 LP Over-Nite Sensation. The last track on the album is one of Zappa's most famous and renowned compositions. Its main features are the drum fills at the beginning and the appearance of Tina Turner and the Ikettes's backing vocals throughout the entire track, notably on the middle and ending sections. According to Barry Miles' biography Zappa, Tina Turner was so impressed with a rough cut of the song, she volunteered herself and her backup singers to sing the "raising my lonely dental floss" backups on the song. Afterwards, Tina called her then-husband Ike Turner into the studio to listen. According to Miles, Ike listened for about a minute, declared, "What the hell is this shit?" and left.