Former Stereophonics drummer Stuart Cable has been found dead at his home in south Wales.
Emergency services attended Mr Cable's house at Llwydcoed near Aberdare, Cynon Valley, at 0500 BST on Monday.
South Wales Police said the cause of death had not been established but there were no suspicious circumstances at this stage.
Mr Cable, who left the Stereophonics in 2003, had hosted his rock show on BBC Radio Wales on Saturday.
South Wales Police confirmed they were investigating the sudden death of a 40-year-old man at an address in Llwydcoed.
Next of kin have been informed.
Mr Cable's former band Stereophonics played at Cardiff City Stadium on Saturday.
Stereophonics were formed in Cwmaman near Aberdare in 1992 by school friends Kelly and Richard Jones along with Mr Cable, who was four years older.
Within five years they were rising stars, supporting bands such as the Rolling Stones and U2.
Mr Cable has said he was planning to leave the band before he was sacked in September 2003.
He also said he had no regrets about leaving the band.
He later formed a new group called Killing for Company, who were due to play at the Download festival Donington Park on Saturday.
The band's new album is due for release to coincide with it.
Mr Cable's autobiography, Demons and Cocktails, was released in 2009.
The autobiography shed light on tensions between Mr Cable and Stereophonics vocalist Kelly Jones which eventually led to the drummer's departure.
Mr Cable revealed the split was mainly sparked off by the Mr Jones' desire to produce the band's third album.
There were also said to be tensions in the band about Mr Cable's burgeoning career as a presenter.
He hosted his own TV show, Cable TV, and radio show, Cable Rock, for BBC Wales.
He has also been involved in a variety of other projects.
In March 2002, he took part in a BBC Wales social action campaign urging young men to look out for the warning signs of testicular cancer.
In autumn 2007 Cable quit the BBC to launch a Cardiff-based branch of rock station XFM, which closed after six months on air.
He was also a presenter for the Birmingham-based commercial radio station Kerrang!
But he returned back at BBC Radio Wales with his Saturday rock show in April.