In 2008 Linkin Park hit the road on the fifth installment of their Projekt Revolution tour, joined by acts including electro-rockers the Bravery, A Perfect Circle guitarist Billy Howerdel's other band Ashes Divide and metalcore stalwarts Atreyu, as well as Soundgarden and Audioslave frontman Chris Cornell. Cornell was out supporting his 2007 solo album, Carry On, and during the trek, he and Linkin Park's Chester Bennington traded off guest appearances in each other's sets. Bennington joined Cornell for his performance of Temple of the Dog's "Hunger Strike," and Cornell returned the favor, coming onstage during the second verse of Linkin Park's "Crawling" to finish the song in duet with Bennington. Watch fan-shot video of such performances, above and below.
Bennington and Cornell were not only musical collaborators but also good friends. After Cornell's death in May, the Linkin Park singer posted an intense, grieving message to Twitter. He wrote of Cornell, "You have inspired me in many ways you could never have known. Your talent was pure and unrivaled. Your voice was joy and pain, anger and forgiveness, love and heartache all wrapped up into one. I suppose that's what we all are. You helped me understand that. I just watched a video of you singing ' A day in the life ' by the Beatles and thought of my dream. I'd like to think you were saying goodbye in your own way. I can't imagine a world without you in it."
Bennington would commit suicide a few months later, dying on Cornell's birthday, July 20th.