Eddie Van Halen deconstructs his collaboration on 'Beat It'

[Gadzooks]

Originally Posted by Brock

Quincy felt he needed a killer guitar solo on the record, so it seems weird to you that he'd call up the best guitar player of the era? ok.

The Beastie Boys had a pretty obvious connection with Slayer, so it's even more likely.

I wouldn't say "even more likely". To me it's just an interesting factoid and an equally unusual non credited performance.