Misfits, whose horror film-inspired punk rock became a major influence on heavy metal but who became embroiled in legal feuds, are reuniting for the first time in 33 years.

The two key members of Misfits, singer and songwriter Glenn Danzig and bassist Jerry Only, will perform together at the Riot Fest which takes place both in Chicago and Denver in September.

The festival and the band both announced the reunion over the weekend, with a promotional poster featuring the line, "They said it would never happen."

Misfits formed in northern New Jersey in 1977 as the punk rock scene exploded both in New York and London. 

Unlike the political anger of British punks or the working-class aesthetic of New York's The Ramones, Misfits took inspiration from horror movies and dressed in Halloween-like outfits with skulls, spikes and leather.

The band lasted only seven years but proved to be a precursor to hard-edged heavy metal bands that emerged in the 1980s.

The two core members last played together in 1983, with Danzig going on to start a metal band under his own name.

Danzig and Only for years fought over the Misfits brand, eventually reaching a settlement through which Only kept playing under the band's name.

Only performed as Misfits with his guitarist brother, who goes by the stage-name Doyle Wolfgang von Frankenstein and who will also take part in the reunion shows.

Only told Rolling Stone magazine that he and Danzig wanted to play again together while they were still both "in their prime."

He said the reunion idea emerged during a legal meeting in January, where he and Danzig went in "wanting to cut each other's throats."

"It was turning into another court battle and it turned into a reunion. We walked out the door knowing we were going to play together. It's a very cool thing," Only said.