Brian Wilson has paid tribute to his long-time guitarist Nicky Wonder after he died aged 59.

The Beach Boys star is in a ''state of shock'' after the Wondermits co-founder, who was part of Brian's touring band since 1999 and played guitar on his albums 'Gettin' In Over My Head' and 'Brian Wilson Presents Smile', passed away in his sleep.

He wrote on his official website: ''Today is a sad sad day.

It is with my deepest regret to tell you that our beloved Nicky Wonder passed away last night in his sleep.

We are in a state of shock as you can imagine.

But we are going to honor him with tonights show. (sic)''

Brian praised ''friendly'' Nicky - whose real name was Nick Walusko - and admitted he will miss the guitarist ''beyond words''.

He added: ''Nicky was my favorite guitar player ever. I always loved the way he used his fingers. He was a real Rock and Roll guy and great singer too.

He was a friendly and very nice person and he was really really funny. He had the best sense of humor.

We are all crying today, he will be missed beyond words.

Our hearts go out to his wife Susan and his entire family, friends and fans.

We love you Nicky. Love & Mercy

Brian Wilson (sic)''

Nicky formed Wondermits with keyboard player Darian Sahanaja in 1992 and the group released five albums, but they haven't dropped a record since 2009's 'Kaleidoscopin': Exploring Prisms of the Past'.

Wondermits signed up to be part of Brian's touring band in 1999, and Nicky and his fellow band member Probyn Gregory played with Brian continuously afterwards.