"Martin Luther King said that it is the greatest offering anybody can bring to the world is service, because greatness is determined through service, and I think what she did was serve her countrymen and serve everyone for 70 years. And the sacrifice that that takes to make when you're 25 years old and to say, 'I'm going to offer myself in sacrifice to my country.' That's what she did."
Oprah was among a wide swathe of celebrities who paid tribute to the Queen after her death at Balmoral, such as Sir Elton John.
The 75-year-old singer said: "Along with the rest of the nation, I am deeply saddened to hear the news of Her Majesty Queen Elizabeth's passing. She was an inspiring presence to be around, and lead the country through some of our greatest, and darkest, moments with grace, decency and a genuine caring warmth. Queen Elizabeth has been a huge part of my life from childhood to this day, and I will miss her dearly."
Showbiz legend Barbra Streisand also paid tribute to the late monarch, lauding her for being a "constant" and "respected" internationally.
The 80-year-old entertainer wrote: "Sad to hear about the passing of Queen Elizabeth II. She was a constant for us all. Respected around the world. May she rest in peace. Barbra."
It comes after Prince William issued a touching tribute to his grandmother.
Taking to Instagram with the couple's newly assumed titles, Prince and Princess of Wales, William told royal followers of his grief for the historic monarch.
Prince Harry issued his own heartbreaking tribute to his late grandmother.
- Additional reporting by NZ Herald
