Not your typical B&B...Earl Spencer opens Althorp estate for a £40k overnight stay

The Spencer family, in a lavish take on the Air B n B format, is offering wealthy guests the chance to sleep at the 500-year-old estate in Northamptonshire, in order to raise money for an international orphanage charity Whole Child.

Earl Charles Spencer and Countess Karen Spencer are set to make the announcement on US network television this Sunday, during a feature on NBC’s On Assignment.

However in preview clips, the family tell presenter Cynthia McFadden a night there “will not be cheap”.

A single night per couple would cost £40,000 - or a private room for a group of 18 would cost £250,000.

When the Spencers were asked “whose idea was it?” by Mrs McFadden, the Countess replied: “It was mine, all the ideas are mine.”

But the Earl continued: “I was instantly on board with it. I have always thought of this as contributing, it’s not just a little bastion or fortress of privilege.”

As part of the show, NBC says it was given a “rare and intimate tour of Althorp” with the Earl and Countess, including a first look at a “never-before-seen area of the mansion”.

Whole Child, the charity set up by Karen Spencer, works to improve conditions for children living in orphanages around the world.

As part of the news feature, NBC says Mrs McFadden travelled with Karen Spencer to Nicaragua where it says independent researchers found her efforts have resulted in “substantial improvements”.

But it says she has also faced criticism for her work as many international aid organizations would rather see orphanages closed.