Grace Slick (born Grace Barnett Wing, October 30, 1939) She was a singer/songwriter, and second and most famous lead singer of Jefferson Airplane. From the mid-1960s to the mid-1990s she also had a solo career
Zappa and Grace Slick
At the Fillmore show (14th November 1970) Slick appeared on stage to announce that Jefferson Airplane and The Grateful Dead would be playing a surprise concert there on the 16th November. Zappa teased: “Do you want Grace Slick to sing Louie Louie? Would that be the ultimate get-off for a Fillmore East audience or what?” Slick declined the invitation.
In 1984 Slick interviewed Zappa at Rock Palace. 
Zappa about Grace Slick
Zappa: "I don't know. Would you presume that "asshole" has a negative connotation? Maybe she likes assholes. Hitler was an asshole. He just had a good p.r. department. Also a good tailor." - Quoted from Dialogue: Frank Zappa, COQ, February 1974.
"He [a gentleman named Erik] gave me a Finnish pornographic magazine that had some girls in it that I couldn't even believe that they would take pictures of 'em. There was one or two in there that looked like Grace Slick but the rest of 'em were hurtin', really hurtin'." - Frank Zappa about the inspiration for Ms. Pinky, liner notes to Lonely Person Devices in You Can't Do That On Stage Anymore Vol. 6.
Grace Slick about Zappa
"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."
"Frank Zappa was pretty good at business. And Frank Zappa didn’t do drugs either. Drugs really get in the way of paying attention to what your accountant’s saying because it’s so boring." - Grace Slick, 2001.