Gossard confirmed that the one-off reunion would happen in 2008, explaining:
Pearl Jam has toured with Mudhoney, so we played with Mark and Steve. But we haven't played with Alex (Vincent, drummer) and Bruce (Fairweather, guitarist) in quite a while. They're both excited about it, from everything I've heard.
The band formed in 1984 and took its name from the Green River Killer that was terrorizing Seattle at the time. The band's first release, a 1985 EP called Come On Down is often described as the first "grunge" record, combining aspects of metal and punk rock and eventually taken into the mainstream by Nirvana.