It looks like Chris Cornell and Duff McKagan aren't the only famous friends who will be joining Mad Season when the band gets back together for a one-off performance on Jan. 30.

Cornell and McKagan had already been announced as guests of the band's surviving members -- Pearl Jam guitarist Mike McCready and Screaming Trees drummer Barrett Martin -- for the concert, which will also boast the involvement of the Seattle Symphony Orchestra. That's all impressive enough on its own, but McCready and Martin apparently also have a few surprises in store.

Diffuser reports that there's a trio of mystery guests on tap for the reunion, which seems to be unfolding as an all-out celebration of the mid-'90s Seattle scene that birthed Mad Season as well as a slew of other bands. As Diffuser's post puts it, "The concert will not only commemorate Mad Season, but it will also celebrate other Seattle greats, including Pearl Jam, Nirvana and more."

Unsurprisingly, the show is already sold out, but fans can still take their shot at winning tickets -- along with $1,000 in travel expenses and a meet-and-greet with McCready and other performers -- by entering a contest sponsored by Pearl Jam's Vitalogy Foundation.

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