Jack Sonni, known as ‘the other guitarist’ in the British rock group Dire Straits led by Mark Knopfler, has died aged 68, the band announced.

The group, famous for classic hits such as ‘Sultans of Swing’ and ‘Money for Nothing,’ posted the news on social media and its website.

Sonni died on Wednesday at the age of 68, the band said, ‘and leaves behind a legacy of musical excellence.’

Born John Thomas Sonni in the US state of Pennsylvania in 1954, he was working at Rudy’s Music Shop in New York when he met Knopfler and his brother David in the late 70s, just after they founded Dire Straits.

Sonni joined the band in 1984, while it was recording its album ‘Brothers in Arms,’ replacing guitarist Hal Lindes.

On the hit album — which helped popularize the CD as a musical format — was the song ‘Money for Nothing,’[ which became the group’s biggest commercial success and was broadcast on loop on the MTV television station.

Sonni played on Dire Strait’s subsequent world tour, as well as at the famous Live Aid charity concert in London.

He embraced the role of being ‘the other guitar player in Dire Straits,’ and used the title on his website.

‘Jack Sonni passed away unexpectedly, leaving behind a deep sense of sadness,’ the band said.

‘The cause of his death remains a mystery at this moment,’ it added. ‘We will provide updates as soon as we receive more information.’