Prince's estate have successfully won a lawsuit to block the release of unheard music by the singer.

Producer George Boxill claimed to have a collection of unreleased songs he worked on with the late musician - who died in 2016 - between 2006 and 2008 and planned to release them himself, even making one track available to buy on iTunes briefly last year.

But the 'Kiss' singer's estate filed legal documents threatening to sue Boxill back in April last year and demanded he return the music to them.

It was claimed Boxill signed a confidentiality agreement when he worked with the star which stated all recordings, ''would remain Prince's sole and exclusive property''. The producer is also said to have agreed he, ''would not use any recordings or property in any way whatsoever.''

TMZ.com has now obtained legal documents which reveal Boxill never responded to the newly filed lawsuit, and the deadline of January 23 has now passed.

The estate have now requested the courts sign off on an injunction, blocking the release of any of the tracks.

This comes just days after Prince's estate promised new music would be released soon.

Estate adviser Troy Carter told Variety: ''I heard some music the other night that was pretty mind-blowing and we're getting some stuff mixed right now ... There will be unreleased Prince music coming soon.''

Last year, Universal Music Group's $31 million distribution deal for Prince's back catalogue was voided over a lack of clarity regarding the terms of the late singer's contract with Warner Bros. Records, the label to which he was signed for nearly the first 20 years of his career.

The contents of Prince's music vaults were moved from his former home in Paisley Park, Minneapolis, to a climate-controlled storage facility in Los Angeles last year, after some of the tapes were found to have deteriorated.

Prince, who was just 57 when he died, had previously revealed the existence of the unreleased music in an interview published after his death.

He said at the time: ''I've never said this before, but I didn't always give the record companies the best song. There are songs in the vault that no one's ever heard. There are several vaults; it's not just one vault.''

The 'Little Red Corvette' singer is to be honoured with a concert event called 'Prince: Live on the Big Screen' that will take place on April 21 2018 at the Target Centre, Minneapolis.

The concert will be part of Celebration 2018, a four-day event in April to honour Prince's life and legacy and will take place at Paisley Park between April 19 and 22.