Official Secrets Act (OSA) is a pop-rock band from London, England. Thomas Burke, Alexander Mackenzie, and Lawrence Diamond formed a band at Leeds University after bonding over an interest in British military history. Michael Evans joined after catching one of their early gigs. The band has drawn inspiration from both British and American guitar-based bands, such as Talking Heads, Futureheads and Blur. OSA was the first band to perform in Black Cab Sessions's the Secret Garden Party Sessions in July 2009.[citation needed]