18 (R U Legal Yet?) is an unreleased instrumental track recorded on 5 December 1988 at Paisley Park Studios in Chanhassen, Minnesota (during the same session as 17 (Penetration), three days before 19 (Jailbait)), during sessions for Madhouse’s third album 24. The track was included as the second track on the album 24, before the album was abandoned.
The track includes spoken phrases of "18 (are you legal yet?)" spoken by Eric Leeds, believed to be his only vocal contribution to a Prince-related track, as well as two spoken phrases of "My father has a shotgun" and "I hope he doesn’t use it" spoken by Paisley Park Studios engineer Heidi Hanschu.
On 21 January 1991, Prince submitted the track (now re-titled Are U Legal Yet?) to Miles Davis, along with Penetration, Jailbait and A Girl And Her Puppy, for his consideration. Prince wanted Davis to record additional trumpet parts before sending them back. Davis instead taught the four tracks to his band and included the track in his live repertoire in March 1991. Contrary to the three other tracks, Are U Legal Yet? was not recorded by Miles Davis and his band in a studio (they recorded new versions of Penetration, Jailbait and A Girl And Her Puppy in late March 1991 at Bauer Studios (Studio 1), Ludwigsburg, Germany).