Sebastian Leslie, 65, says borrowed money from his actress daughter and her husband, actor Kit Harrington, after he lost the 16th centruy Lickleyhead Castle in Aberdeenshire.
The clan chief told newspaper The Scottish Sun: “Rose and Kit helped financially.
“I can’t tell you how much they gave me but they were very generous. Asking your daughter for money is a very difficult thing to do.
"But it will be a price worth paying if we can get justice for 3,000 people.”
The castle, where Rose grew up and which was once on sale for £1.3 million, was repossessed as Mr Leslie faced court action from a loan company battling to recover debts.
He told the newspaper: “I had to reveal this level of corruption that exists within the Bank of Scotland. We needed to fight this and that’s why it went to the wire and why it’s done so much harm to the family.”
Lickleyhead was built by the Leslie clan around 1560.
The family also own Wardhill Castle in Inverurie.
A spokeswoman for the bank said: "If Mr Leslie has additional information to support his claims, we would ask him to provide documentation which can be investigated."