Eagles star Joe Walsh struggled to watch the band's candid documentary as he felt "uncomfortable" revisiting his substance abuse issues on film. The Hotel California hitmaker battled drug and alcohol addiction during his time in the group, and he didn't enjoy looking back on his past problems in documentary History of the Eagles. However, Walsh, who has been clean for more than 19 years, admits the filmmakers had to show his addictions on screen to stay true to the band's history. He tells Britain's The Daily Telegraph, "I was a little uncomfortable with the old footage of me, when I was a mess. But it was important that it was in there, 'cos we were trying to tell the truth. I ended up (an) alcoholic and totally dependant on various other substances. I mean, I had a blast but I took it too far." The rockers reunited in 1994 after a 14-year hiatus on the condition that Walsh cleaned up his act, and the guitarist admits he had to learn how to play sober. He adds, "I played music high for so long, I didn't know how to do it sober... It was terrifying going on stage. I had to learn how to do everything all over again, sober." The History of the Eagles was released in U.S. cinemas in January (13).