Sky News has learnt that Sir Elton, whose appearance at this year's Glastonbury Festival drew a television audience of millions, and his husband, David Furnish, are among the investors in a new funding round for Audoo.

City sources said the $5m (£4.1m) injection would be announced publicly on Tuesday.

The capital-raising adds Sir Elton's name to those of ABBA's Bjorn Ulvaeus and MPL Ventures, Sir Paul McCartney's investment company, as backers of the five-year-old business.

Audoo, which was established by former musician Ryan Edwards, aims to address the perennial issue of public performance royalties, in order to ensure musicians are rewarded when their work is played in public venues.

Mr Edwards is reported to have been motivated to set up the company after hearing his own music played at football stadia and in bars, without any payment for it.

Estimates suggest that artists lose out on as much as $3bn globally in unaccounted royalties each year.

London-based Audoo uses a monitoring device - which it calls an Audio Meter - to recognise songs played in public venues, and which is said to have a 99% success rate.

It has struck what it describes as industry-first partnerships with organisations including the music licensing company PPL/PRS to track and report songs played in public performance locations such as cafes, hair salons, shops and gyms.

The Audio Meter is now present in 10 countries across four continents, according to Audoo.

The addition of Sir Elton, whose final gig of his farewell tour took place in July, cements Audoo's share register's standing as arguably one of the most star-studded of any British start-up.

In a statement sent to Sky News, Sir Elton said: "Working as a musician can be seen as all glitz and glamour but for the vast majority of artists, especially new and emerging acts, this isn't the case.

"It's often brutally unfair and this sadly extends into being paid correctly.

"Right now, artists are not being paid accurately for their plays because the data simply doesn't exist.

"People have given up on their dreams and we've lost talent and future stars because of this disparity.

"That's why we've invested in Audoo and their world-class technology, to help create a more transparent system for everyone, and ultimately to keep the music alive."

The latest funding round takes the total amount of money raised by Audoo since its launch to $22m.

Mr Edwards has spoken of his desire to establish a major presence in Europe and the US because of their status as the world's biggest recorded music markets.

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"Being able to draw on the support of artists in our mission to revolutionise the royalty space has been key to Audoo's success, and we are incredibly proud to welcome even more icons to aid in the next stage of our journey," Mr Edwards said.

"With Elton and David's strategic investment, we will be able to continue to champion and deliver a fairer, and more transparent music industry for creatives to benefit for generations to come.

"We look forward to welcoming more international partners, licensees and creators to join us on this industry-changing journey."

Audoo has moved in recent months to recruit several heavyweight industry figures, including the appointment of Nigel Elderton, a music publishing veteran, as its chairman.