Andrew had vehemently denied Giuffre's accusation that she was forced to have sex with him when she was just 17.
The Duke of York used Beatrice as an alibi, claiming he took the princess to a Pizza Express restaurant in Woking, Surrey when Giuffre's alleged the assault occurred.
His legal team has been requested to supply evidence to back up the pizza visit. As a result, both Beatrice and Ferguson could be called in for questioning.
According to the Times, the interview could take place in June.
Sources revealed to Page Six that Ferguson is sticking by her former partner's side despite the allegations.
"Sarah is fully behind Andrew and is part of his team. No one from inside Buckingham Palace has been involved in Prince Andrew's case, or even knows anything much. It's really just the Duke of York, Fergies and his lawyers," the insider claimed.
On Wednesday, Judge Lewis A. Kaplan denied Andrew's request to dismiss Giuffre's lawsuit. The judge ruled the prince will have to stand trial, which is has been scheduled for September. It won't be cheap either.
The proceedings are expected to cost the royal millions of dollars in legal fees — not to mention his already damaged reputation.
Andrew has allegedly been forced to sell his $23 million Swiss ski chalet to cover the bills after the Queen refused to help him financially.
As Radar previously reported, Buckingham Palace issued a statement on Thursday announcing that Queen Elizabeth has stripped Andrew of his military titles and royal patronages amid the lawsuit.
After losing his honors, Andrew will be facing the suit as a "private citizen" and is not entitled to any help or aid from the royal family.
"With The Queen's approval and agreement, The Duke of York's military affiliations and Royal patronages have been returned to The Queen," the statement read. "The Duke of York will continue not to undertake any public duties and is defencing this case as a private citizen."