The Duke of York told bankers to call his Buckingham Palace office if there were any concerns over payments from an alleged fraudster.
Selman Turk assured officials looking into a £750,000 ($1.42m) "wedding gift" for Princess Beatrice that Prince Andrew had authorised him to pass on the details of palace aides to confirm.
The Duke and his family have been named in a High Court battle where Turk, 35, is accused of defrauding Nebahat Evyap Isbilen, a 77-year-old Turkish millionairess.
Out of around £40 million ($75.8m) he is alleged to have stolen from her, court papers suggest Turk facilitated payments to the Duke totalling £1.1million ($2.08m), to his ex-wife Sarah Ferguson of £225,000 ($426,000) and to Princess Eugenie of £25,000 ($47,000).
The Telegraph has revealed that the payments were made after Turk and the Duke were introduced in early 2019 by Tarek Kaituni, a convicted Libyan gun smuggler.