Eldon Howard
Eldon Howard was a British screenwriter.
She was the mother- in- law of Edward J. Danziger and wrote a number of the screenplays for films by his company Danziger Productions.
Maria Thins
Maria Thins( c. 1593 – 27 December 1680) was the mother- in- law of Johannes Vermeer and a member of the Gouda Thins family.
Marian Shields Robinson
Marian Lois Robinson( née Shields; born July 29, 1937) is the mother of Michelle Obama, former First Lady of the United States, and Craig Robinson, a basketball executive, and the mother- in- law of former U.S. President Barack Obama.
Charlotte Casiraghi
Charlotte Marie Pomeline Casiraghi( born 3 August 1986) is the second child of Caroline, Princess of Hanover, and Stefano Casiraghi, an Italian industrialist.
She is eleventh in line to the throne of Monaco.
Her maternal grandparents were Rainier III, Prince of Monaco, and American actress Grace Kelly.
She is named after her maternal great- grandmother, Princess Charlotte, Duchess of Valentinois.
She was christened on 20 September 1986.
Her godparents are Albina du Boisrouvray and Stefano Casiraghi's brother- in- law, Massimo Bianchi.
Vera Miletić
Vera Miletić (Serbian Cyrillic: Вера Милетић; 8 March 1920 – 7 September 1944) was a Serbian student and soldier.
She was notable for being the mother of Mira Marković, posthumously making her the mother-in-law of Serbian president Slobodan Milošević.
Priscilla Pointer
Priscilla Marie Pointer( born May 18, 1924) is an American stage, film and television character actress.
She began her career in the theater, including productions on Broadway.
Later, Pointer moved to Hollywood to act in films and on television.
She is the mother of Amy Irving, therefore making her the former mother- in- law of filmmakers Steven Spielberg and Bruno Barreto and the mother- in- law of documentary filmmaker Kenneth Bowser, Jr.
Stefano Casiraghi
Stefano Casiraghi (8 September 1960 – 3 October 1990) was an Italian speedboat racer, socialite, and businessman.
He was the son of Giancarlo Casiraghi and Fernanda Biffi, and became the second husband of Princess Caroline of Monaco.
He was famous for having set a speed record in speedboat racing and was, at the time of his death in a racing accident, the world champion of offshore powerboat racing.
Caroline, Princess of Hanover
Caroline, Princess of Hanover (Caroline Louise Marguerite Grimaldi; born 23 January 1957), is the eldest child of Rainier III, Prince of Monaco, and the American actress Grace Kelly.
She is the elder sister of Prince Albert II and Princess Stéphanie.
Until the births of her niece and nephew, Princess Gabriella and Prince Jacques, in December 2014, she had been heiress presumptive to the throne of Monaco since 2005, a position which she previously held from 1957 to 1958.
Caroline is married to Ernst August, Prince of Hanover (born 1954), the heir
to the defunct throne of the former Kingdom of Hanover, as well as the heir male of George III of the United Kingdom.
Baroness Gösta von dem Bussche-Haddenhausen
Baroness Gösta von dem Bussche- Haddenhausen( 26 January 1902 – 13 June 1996) was the mother of Prince Claus of the Netherlands, who was the Prince Consort of Queen Beatrix of the Netherlands, thus making her the mother- in- law of the former Dutch Queen.
She is also the paternal grandmother of King Willem- Alexander of the Netherlands, who is the current Dutch King.
Cornelia (mother of the Gracchi)
Cornelia( c. 190s – c. 115 BC) was the second daughter of Publius Cornelius Scipio Africanus, the hero of the Second Punic War, and Aemilia Paulla.
She is remembered as a prototypical example of a virtuous Roman woman.
She was the mother of the Gracchi brothers, and the mother- in- law of Scipio Aemilianus.

Question: Who is the mother-in-law of Stefano Casiraghi?
Answer: Grace Kelly