Robert De Niro owed $6.4 million to the IRS for his 2013 tax return, but it appears he just learned of it. The Oscar winner’s tax debt surfaced in documents first uncovered by the Smoking Gun. Mr. De Niro has an estimated worth of over $200 million, and is reputed to spend $125,000 a month on his rental on Central Park West. In that sense, this tax bill doesn’t seem so large.

But it was unpaid, as the notice to New York City’s Department of Finance revealed. That is what an IRS lien filing is all about. But right away, Mr. De Niro took action. In fact, his spokesman Stan Rosenfeld said the problem occurred because the IRS delinquency notices had been sent to an old address. As soon as the actor learned of the tax lien, he had a check for the full amount hand delivered to the IRS.

Not every tax debtor can write a check of this size on the spot. In any case, it may seem hard to believe that someone could not know about a $6.4M bill. Yet celebrities seem often to find themselves in this position. Despite high earnings, their tax bills may slip through the cracks. They may have managers or other professionals handle all of such details.

And make no mistake, this didn’t occur because of just one missed notice. There would have been multiple notices that went unanswered, escalating the dispute. As one might expect, that usually means extra interest and penalties. The IRS can file a Notice of Federal Tax Lien only after:

• IRS assesses the liability;
• IRS sends a Notice and Demand for Payment; and
• You fail to fully pay within 10 days.

The IRS files a notice of lien so creditors know. IRS tax liens cover all property, even if acquired after the lien filing. The courts use it to establish priority in bankruptcy proceedings and real estate sales. IRS liens last 10 years, and usually release automatically if IRS has not refiled them. However, you’re better off to get them removed immediately.

Getting the IRS to release a lien usually involves: (1) paying the tax, interest and penalties; or (2) posting a bond guaranteeing payment. Even then, the IRS may take 30 days. State or local government charges to file and release the lien are added to the amount you owe. See IRS Publication 1450, Request for Release of Federal Tax Lien.

Liens and seizures aren’t the same. The lien just makes sure the IRS eventually gets paid. A seizure involves forced collection so the IRS can sell property and get paid now. But occasionally, even the IRS makes a mistake.For example, it happened to Dionne Warwick, and she proved that an IRS tax lien can be wrong.

More recently, comedian Chris Tucker had a $14 million IRS lien. He is witty, but it is hard to outwit the IRS when it moves to collect on a huge tax bill, particularly when they start to snowball. Tucker had a new lien adding $2.5 million to a previous $12 million. Fortunately, Mr. Tucker reached a deal settling the huge bill.