A newspaper is calling for a change to chart rules to allow Prince's new CD, which is being given away in the Mail on Sunday, to enter the album charts.
Planet Earth is Prince's 24th studio album
Planet Earth, a covermount in Sunday's Mail, is being "penalised" for being the first album to be launched in a paper, says the publication's manager.
Stephen Miron has written to the Official Charts Company, saying he is prepared to consider legal action.
As a free giveaway, chart rules say the CD is ineligible for chart inclusion.
Prince's new album, which will be distributed in approximately 2.9m copies of the Mail on Sunday this weekend, "falls out of those parameters", according to Mr Miron.
"It's a first, it's a one-off, so we feel we can challenge them," he said, with regard to the current chart rules.
He also suggested there would be "a lot of peer pressure" from fans to make the Official Charts Company reconsider their position.
The Official Charts Company were not immediately available for comment.
The chart company has also claimed it would be hard to prove that a newspaper giveaway consisted of "genuine musical purchases", and sales could not be accurately audited.
But Mr Miron says the newspaper will be able to indicate how many CDs have been taken up by measuring the difference between regular sales and those with a covermount.
If deemed eligible for chart inclusion, the album is expected to enter the chart on 22 July.
The deal between Prince and the Mail on Sunday led the UK arm of his record label, Sony BMG, to suspend its planned release of the album.
The US pop star, whose latest album marks his 24th studio release, is due to play 21 concert dates in London later this year.