Her Majesty, then Princess Elizabeth, swapped her dresses for a boyish outfit to play Aladdin in 1943. She wore a gold brocade and turquoise jacket, with dungarees in the same shade and matching hat.
A young Philip was among 400 people in the audience in the Waterloo Chamber at Windsor Castle.
The Queen's former governess Marion Crawford said: "The pantomime went off very well.
"I have never known Lilibet more animated.
"There was a sparkle about her none of us had ever seen before."
Elizabeth said to her governess: "Who do you think is coming to see us act, Crawfie? Philip!"
Her sister Princess Margaret played Princess Roxana in the show.
She wore a red silk dress and matching jacket.
The play was one of a series of Christmas pantomimes during World War Two as the princesses stayed at Windsor Castle - away from the bombing in London.
READ MORE: Queen 'very unlikely' to stop public duties 'unless forced'
The pantomimes between 1941 and 1944 were to raise money for the Royal Household Wool Fund, which supplied knitting wool to make comforters for soldiers.
Six costumes worn by the princesses at wartime pantomimes are set to go on display at Windsor Castle from November 25 2021 to January 31 2022.
The Aladdin performance came after Elizabeth first met Philip in 1934.
DON'T MISS
Prince Andrew will be 'invisible' for Queen's Platinum Jubilee events [INSIGHT]
Meghan Markle quitting Royal Family was 'tragedy' [ANALYSIS]
Queen has Royal Family 'quite concerned' with reluctance to share duty [VIDEO]
The pair met at the wedding of Princess Marina of Greece and Denmark to Prince George, Duke of Kent.
Their engagement was announced on July 9 1947.
And they tied the knot on November 20 1947 at Westminster Abbey.
The Queen and Philip were married for 73 years at the time of the Duke of Edinburgh's death.
The Duke died peacefully aged 99 at Windsor Castle in April.
The Queen famously described her beloved husband as her "strength and stay".