The 32-year-old beauty revealed the late royal's relative jokingly asked her to marry him after they chatted backstage in London on MArch 28.
Lady D's nephew, Louis Spencer (son of her brother, Charles Spencer) got to meet Nicki at her London concert on Saturday, March 28 and the 32-year-old beauty revealed the late royal's relative jokingly asked her to marry him after they chatted backstage.
The 'Starships' hit-maker posted a cheeky snap of her posing with Viscount Althorp, who is the oldest son to Charles Spencer.
She wrote below: "The Royal Family stopped by. @louisspencer Nephew of Princess Diana - he said he wants to marry me #LONDON #ThePinkprintTOUR (sic)".
The accompanying photo sees the hip-hop bad girl cosying up to the handsome 21-year-old; clad in a see-through black top through which her bra is clearly visible. (Nicki's racy attire probably wouldn't go down well in the Spencer household).
Nicki followed up with another picture, captioning it, "Check out our wedding photo. no honestly it was such an honor to have you guys."
She also posted a shot with the handsome artistocrat's sister Lady Kitty Spencer, writing, "His beautiful sister @kittyspencer8 #LONDON #ThePinkprintTOUR".
The Princess of Wales' family have managed to fly under the rader since she passed away in a car crash in Paris on 31 August 1997.