Ant and Dec have asked a High Court judge to help them obtain information about deals in which they bought and sold Banksy artworks, after claiming an intermediary took "secret and unauthorised profits".
The TV hosts say they paid £550,000 for one set of Banksy works but the seller apparently only received £300,000, and they want to know what happened to the other £250,000.
They also have "similar concerns" about being deprived of "a substantial sum" from selling 22 items, the court was told on Tuesday.
The pair have asked a judge to issue a court order to force an art dealer to hand over his information about the transactions and the operations of a separate art consultant who acted on the stars' behalf.
Ant and Dec enlisted the consultant, who has not been named and was referred to as X in court, to help them buy, sell and loan the artworks as they built up a contemporary art collection.
