Steven Tyler joined the 'American Idol' judging panel ''out of anger''.

The Aerosmith frontman admits he took a ''bit of a risk'' signing up for the talent show - which he quit earlier this year after two series - because he didn't know what he was doing on the programme at first, but he was desperate to do something aside from making music with the group.

He said: ''It was great, it was a bit of a risk in the beginning, I wasn't sure what I was doing, I did it out of anger, the band was going through stuff and I went away somewhere to get a good look at what was going on, I'd just finished writing my book and a bunch of things and I just said, 'Get me Idol'.''

Steven admits he was a ''little unsure'' initially if he'd chosen the right career move by signing up to 'American Idol', but he soon realised it was a ''good thing'' when Aerosmith's sales skyrocketed.

He added in an interview with Absolute Radio's Russ Williams: ''I wrote a song for this Japanese movie with Marty Fredrickson, a guy we write with, and with Kara [DioGuardi], who was a judge on 'Idol', she was like, 'Well why don't you just do 'Idol'?' And I thought about it for a couple of weeks and I said, 'Let's just do it.'

''So I was a little ambivalent, I wasn't sure, but after the first year the Aerosmith ratings went up 270 per cent, every time someone sang 'Dream On' or 'Don't Want to Miss a Thing' you know our songs went up on iTunes, it was a good thing.''