The former Guns N' Roses bassist alleges he was contacted by an official at Fox Tv in the late 1980s who told him the network's new animated comedy show had a product called Duff Beer.
MCKagan, who claims cartoon bosses chose the moniker in honour of his booze-fuelled lifestyle, was happy to agree - but since The Simpsons became a worldwide phenomenon, he rues not licensing his name officially.
He tells British newspaper The Independent, "I knew nothing about branding yourself then or the royalties off it. I just thought cool, they wanna (sic) use my name and boom, The Simpsons was born. Yeah, if I had a nickel for every time... but it's fine."