System of a Down’s Serj Tankian made a surprise appearance during Prophets of Rage’s set at Germany’s Rock im Park Festival to pay tribute to Chris Cornell with a cover of Audioslave’s “Like a Stone.”

Both System of a Down and Prophets of Rage, which features Cornell’s Audioslave band mates Tom Morello, Brad Wilk and Tim Commerford, were on the lineup for the festival in Nuremberg, Germany. Last week Prophets of Rage posted a video of them rehearsing the Audioslave song.

Chris Cornell last sang “Like a Stone” in January during a one-off Audioslave reunion at an anti-Trump benefit concert, the band’s first performance together in nearly 12 years.

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