The 44-year-old singer pours his heart out on the group's upcoming single 'Back To The Shack', on which he admits he hasn't always made the right decisions on behalf of the 'Buddy Holly' hitmakers and at times he went too far.
He said: ''Lyrically I'm talking about how I feel bad about some of the musical experiments I took Weezer on and how I want to make a classic alt-rock record.
''Sometimes I've gone over the edge. Right now it feels like we want to go back and balance it out with some more classic elements of geek rock.
''There's definitely still some experimentation but it sounds like experiments that only Weezer could do.''
Rivers also used his feelings to help inspire him to pen Weezer's upcoming ninth album, 'Everything Will Be Alright In The End', which partly focuses on the group's relationship with father-figures.
He added to NME magazine: ''My father was in the army, stationed in Germany, when I was growing up, so I didn't see him much. That gave me a lot to write about, and I explored the father figure theme in other ways, too. There's a song called 'Eulogy For A Rock Band' about Weezer's musical forefathers. 'The British Are Coming' is about the American colonies' relations with their imperial father, the British Empire. And 'Foolish Father' could be me singing about my father or me singing about my daughter.''
Spencer Morrill believed he was in a relationship with the singer and that she was hiding messages for him in her songs.
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Roberts had left the band in 2012, due to problems with blood circulation and other health issues.
The popstar turned actress is back in the studio.