Grace Slick
Grace Slick (born Grace Barnett Wing, October 30, 1939) jammed with the Hot Rats Band in the opening show at The Fillmore on November 13th, 1970. She was a singer/songwriter, and lead singer of Jefferson Airplane; she also was a solo artist for nearly three decades, from the mid-60s to the mid-90s.
Zappa wanted (according to a 1969 Rolling Stone interview) Slick to appear in Captain Beefheart vs. The Grunt People. They had written and recorded Would You Like A Snack? together.
"Frank Zappa's house in the canyon, which I visited several times, looked exactly like a troll's kingdom. Fuzzy haired women lounged in long antique dresses, and naked children ran to and fro while Frank sat behind piles of electronic equipment discussing his latest ideas for orchestrating satirical hippie rock music. Never a druggie, Frank openly made fun of the very counter-culture he was helping to sustain."
See also: Dialogue: Frank Zappa