LL Cool J Restores Audi from 'BAD' Album, Donates It to Rock & Roll HOF

LL Cool J isn't just receiving his induction into the Rock & Roll Hall of Fame, he's also giving back to the org by donating something special ... with horsepower to spare.

You might've seen clips of the Queens-born rapper doing his thing on stage when he got the huge honor this past weekend, but what you didn't see is LL hooking up the HOF with a red Audi that's near and dear to his heart.

The whip was featured on the cover of his second album, "BAD" -- which came out in 1987 -- and LL sought out the help of custom auto body shop Unique Rides in NYC to restore it for the Hall.

The shop's owner, Will Castro, tells TMZ ... LL approached him about this last year during the pandemic, asking if the UR crew could help him out.

Little back story on the ride -- it was one of LL's first big purchases after signing his initial Def Jam record deal ... which explains why he held on to it after all these years. Castro says it was being stored at LL's grandma's house in NYC for nearly 3 decades!!!

He says it was in pretty bad shape -- it's an '87 Audi 5000, after all, and as you can see, it was pretty torn up from the inside out.

We're told the tweaks made include ... new bodywork, a fresh paint job, installing a custom 2-tone black leather interior with red piping, a full stereo system with Blaupunkt cassette deck (truly old school), amps and subs, red lighting, putting in OG BBS wheels and a full engine rebuild.