Eddy Amoo, one of 1970s soul band The Real Thing – who had hits including You To Me Are Everything and Feel the Force – has died at the age of 73.
Amoo was a vocalist and songwriter with the pioneering Liverpool quartet.
Friend Simon Sheridan said he had died suddenly in Australia and paid tribute to him as an "inspirational character".
Sheridan told the BBC The Real Thing were "huge pioneers of black music in the UK" and the first all-black British band to have a UK number one single.
That was You To Me Are Everything, which topped the charts in 1976. The song returned to the charts in 1986, when it reached number five.
Amoo started his career leading Merseybeat a capella group The Chants in the 1960s. John Lennon was said to have championed them, and they were represented by The Beatles' manager Brian Epstein for a short time.
After their demise, Amoo joined his younger brother Chris in The Real Thing.
Their other hits included Can't Get By Without You, while French house duo The Freeloaders took them back into the charts in 2005 by sampling their song Love's Such a Wonderful Thing.
Another of their tunes, Children of the Ghetto, was covered by artists including Philip Bailey and Mary J Blige.
Sheridan, who has been making a documentary about the group, said Amoo's death was "a complete shock".
He said: "These were four working class boys from a tough neighbourhood, from Toxteth, and they completely changed the face of British music in 1976."
A statement from the band said: "It is with great sadness that we share the passing of our brother and inspiration, Eddy Amoo.
"Eddy was a showman, a songwriter, and a legend in British music."