Back in 2007, Led Zeppelin reunited for bombastic a two-hour set at London's O2 Arena as part of a tribute concert for Atlantic Records founder Ahmet Ertegun. The film documenting that legendary one-off, Celebration Day, is slated for home release on November 19th, and with the band insisting that another reunion isn't coming, you can take solace in this exclusive clip of the rock icons blasting their way through the Physical Graffiti classic "Kashmir."