Barbra Streisand met Queen Elizabeth's son for the first time on the set of her 1974 film, Funny Lady, after which he called her his "only pin-up".
The duo crossed paths again when Barbra performed at Wembley Arena in 1994, as part of a charity gig for the Prince's Trust charity, and according to the 2006 biography Barbra - The Way She Is the heir to the throne tried to romance the singer after his separation from Princess Diana but while he was dating Camilla Parker-Bowles.
Barbra, who was first married to actor Elliott Gould from 1963 until 1971, married her second husband James Brolin in 1998.
Prince Charles went on to marry his longtime love Camilla, now Duchess of Cornwall, in 2005.
Prince Charles wasn't the only member of the British royal family the Hollywood star called out during Sunday night's performance.
In her opening number, Streisand changed the lyric to her song When the Sun Comes Out to honour the Duchess of Sussex: "When the sun begins to sparkle, like that ring on Meghan Markle!"
Meghan and Prince Harry celebrated the christening of their first child baby Archie Harrison at Windsor Castle last weekend, in front of a select group of 25 guests including Prince William, Kate Middleton, Duchess of Cambridge, and Princess Diana's sisters Lady Jane Fellowes and Lady Sarah McCorquodale.