Rivers Cuomo has enjoyed massive success as lead singer and principal songwriter of rock band Weezer, selling more than 10 million records in the US.
Cuomo says recording demos is "the most exciting adventure"
UK hits for the 37-year-old's band include Buddy Holly and Beverley Hills.
Cuomo's new solo album, Alone: The Home Recordings of Rivers Cuomo, contains a selection of the hundreds of demos he has recorded between 1992 and 2007.
Why was it important to release these demos?
I think there's a quality that these demos have that I don't really get on a full production Weezer album. Something I really like is the intimacy - I don't get that on a Weezer record.
What are the main differences between working with Weezer and working on your own?
Weezer are expected to release their sixth album this year
Working with the band is more challenging because you have all these different guys with different opinions.
It's really hard to keep fighting for my own vision and yet still have an open mind to get ideas from the other guys. The result of course is much stronger but it's more difficult.
In the album sleeve notes you say that, in a recording of you as a 14-year-old in a band, you were "the pushy one". Does that still ring true and do you think a lead singer usually is the pushy one?
When I hear that track it reminds me of me now still. I still have that quality where I get this vision in my mind and then I'm trying to convince everyone else to follow along and I can be pushy.
I've learned over the years that it can be dangerous if you have tunnel vision and you don't consider what other people are thinking, so I'm way more open now than when I was 18 .
You've made a video for the song Blast Off! taken from Alone. What's the song about?
That song was written to be part of a musical and it's one of the first songs in the show. It's about taking off on a space mission.
There's that feeling of excitement and adventure and it's kind of what was going on in my life in 1995 as Weezer was really starting to take off.
What's the idea behind the video?
I happened to be in Japan staying at my wife's parents' house and my manager called and said `hey, we need a video'. It was stuff I was doing every day anyway but I just had my wife bring along a camera.
Every morning we would walk to the park and do these exercises they do all over Japan. They bring their transistor radios and they tune into their exercise programme - it's really cute.
In the Blast Off! video you're sporting a great moustache and you've had a full, bushy beard before. Why should men experiment with facial hair?
Different kinds of facial hair really change the way people view you and it really changes the way you feel. I think it's a pretty easy way to step into a completely different role in life and see what it feels like.
Apart from two songs, you play all the instruments on the demos - including the clarinet. How do you learn them?
Usually I have friends who have an instrument I've never tried before so I borrow it and try to figure out. I never get very good but good enough play a demo.
Cuomo advises experimentation with facial hair
Would you be recording demos if you hadn't became a successful rock star?
I don't know. I think I would naturally gravitate towards whatever I felt like people wanted out of me - what the world wanted out of me. If they didn't want my music, I'd figure on some other way to express myself creatively that they would appreciate more.
You say you have in the past gone from very complex arrangements to stripped-back songs. Which do you prefer?
I love them both. I guess I need balance in my life and I like to be stimulated in different ways. After I've taken on one kind of challenge then I want to take on the opposite kind of challenge.
You like soccer and you're an LA Galaxy fan to boot. Has the Beckham move to Galaxy been a success?
It's been a huge success. He hasn't played many games because he was injured but, for example, there was one game Galaxy played in New York and I think there were 50,000 there. The game was incredible. I'm so glad Beckham's here, he brings magic.
River Cuomo's new album Alone came out in the UK on Monday. He talked to BBC News entertainment reporter Liam Allen.