Prince, the iconic “Purple Rain” singer, is facing a green drain on his estate. The IRS charges his estate has been under-valued by almost half.

Prince, real name Prince Rogers Nelson, died in 2016 and his estate was placed in the administrative hands of Comerica Bank & Trust.

Prince’s siblings appear to be the biggest losers, so far.

They claimed they have yet to receive any money from his estate.

Sisters Sharon and Norrine and brother John Nelson have filed their own a legal claim seeking “payment for services and efforts provided to the estate.”

They say they have spent “considerable time and investment in business matters related to the Estate.

“Unlike others, who have performed services for the Prince Estate, SNJ has not received any financial sums for numerous and repeated services they have contributed to the Estate.”

They also allege that although they have not received any money, others have been paid “millions.”

The court documents added that they have had to rely “solely on their pension, social security, personal savings and loans from friends to cover the costs needed to support the Prince Estate despite the millions paid to advisors, attorneys and others approved by the court.

“As this court is aware, the estate has now been on-going for over three years. In this time, millions have been paid to the Personal Representatives, their accountants, attorneys, and legal advisors.”

The bank ended up valuing the estate at $82.3 million, but the IRS counter after its own audit, claiming the singer’s final net worth was more like $163.2 million.

At the center of the dispute is the Purple Rain’ hitmaker’s musical publishing and recording interests, according to the hometown newspaper, the Star Tribune.

The IRS discovered a $15 million difference in figures valuing the fair market price of Prince’s ownership of NPG Music Publishing, and another $11 million valuation gap in his interest in his musical compositions.

As well as the revised tax bill, the IRS has also fined the estate  $6.4 million in an “accuracy-related penalty.”

But the dispute is by no means resolved.

Dennis Patrick, an estate planning lawyer who is not involved with the proceedings, said it could take “several years” for the dispute to be resolved.

He described valuing l arge estates as “way more of an art than a science.”

“What we have here is a classic battle of the experts – the estate’s experts and the IRS’ experts,” he explained.

“It could be several years before they get this worked out if they don’t agree to a settlement. It depends on how hard the IRS is digging in its heels.”