Question: Siobhan Dillon starred in what musical based on Billy Wilder's Academy Award-winning 1950 film of the same title?
Context: The Emperor Waltz (German: "Ich küsse Ihre Hand, Madame" ) is a 1948 American musical film directed by Billy Wilder and starring Bing Crosby and Joan Fontaine.  Written by Wilder and Charles Brackett, the film is about a brash American gramophone salesman in Austria at the turn of the twentieth century who tries to convince Emperor Franz Joseph to buy a gramophone so the product will gain favor with the Austrian people.  "The Emperor Waltz" was inspired by a real-life incident involving Franz Joseph I of Austria.  Filmed on location in Jasper National Park in Canada, the film premiered in London, Los Angeles, and New York in the spring of 1948, and was officially released in the United States July 2, 1948.  In 1949, the film received Academy Award nominations for Best Costume Design and Best Music, as well as a Writers Guild of America Award nomination for Best Written American Musical. Robert Emmett O'Connor (March 18, 1885 – September 4, 1962) was an American film actor.  He appeared in 204 films between 1919 and 1950.  He is probably best known as the warmhearted bootlegger Paddy Ryan in "The Public Enemy" (1931) and as Detective Sergeant Henderson pursuing the Marx Brothers in "A Night at the Opera" (1935).  He also appeared as Jonesy, (the older Paramount gate guard) in Billy Wilder's 1950 film "Sunset Boulevard".  He also made a cameo appearance at the very beginning and very end of the Metro-Goldwyn-Mayer cartoon short "Who Killed Who? " (1943). Love in the Afternoon is a 1957 American romantic comedy film produced and directed by Billy Wilder which stars Audrey Hepburn and Gary Cooper.  The screenplay by Wilder and I.A.L. Diamond is based on the Claude Anet novel "Ariane, jeune fille russe" (trans., "Ariane, Young Russian Girl"), which had been filmed as "Scampolo" in 1928 and "Scampolo, ein Kind der Strasse" (trans., "Scampolo, a Child of the Street") in 1932, the latter with a script co-written by Wilder.  Wilder was inspired by a 1931 German adaptation of the novel "Ariane" directed by Paul Czinner. Sabrina ("Sabrina Fair/La Vie en Rose" in the United Kingdom) is a 1954 American romantic comedy film directed by Billy Wilder, adapted for the screen by Wilder, Samuel A. Taylor, and Ernest Lehman from Taylor's play "Sabrina Fair".  It stars Audrey Hepburn, Humphrey Bogart, and William Holden.  This was Wilder's last film released by Paramount Pictures, ending a 12-year business relationship with Wilder and the company.  The film was selected for preservation in the United States National Film Registry by the Library of Congress in 2002. Siobhan Patricia Dillon (born 1 September 1984 in Lichfield, Staffordshire) is an English actress and singer, who rose to fame when she performed in the British talent show-themed television series "How Do You Solve a Problem Like Maria? " on BBC One in 2006.  Since then, Dillon has performed in the West End, playing the roles of Sandy in "Grease" at the Piccadilly Theatre, Vivienne Kensington in "Legally Blonde" at the Savoy Theatre, Sally Bowles in "Cabaret", Molly in "Ghost the Musical" at the Piccadilly Theatre, Ellen in "Miss Saigon", and Betty Schaefer in "Sunset Boulevard" with the English National Opera.  Siobhan reprised this role at the Palace Theatre in New York City. The Spirit of St. Louis is a 1957 aviation biography film in CinemaScope from Warner Bros., directed by Billy Wilder, produced by Leland Hayward, that stars James Stewart as Charles Lindbergh.  The screenplay was adapted by Charles Lederer, Wendell Mayes, and Billy Wilder from Lindbergh's 1953 autobiographical account of his historic flight, which won the Pulitzer Prize in 1954. Some Like It Hot is a 1959 American romantic comedy film set in 1929, directed and produced by Billy Wilder, starring Marilyn Monroe, Tony Curtis, and Jack Lemmon.  The supporting cast includes George Raft, Pat O'Brien, Joe E. Brown, Joan Shawlee, and Nehemiah Persoff.  The screenplay by Billy Wilder and I.A.L. Diamond is based on a screenplay by Billy Wilder and Michael Logan from the French film "Fanfare of Love".  The film is about two musicians who dress in drag in order to escape from mafia gangsters whom they witnessed commit a crime inspired by the Saint Valentine's Day Massacre.  The film was produced in black and white, even though color films were increasing in popularity. Sunset Boulevard is a musical with book and lyrics by Don Black and Christopher Hampton (with additional lyrics by Amy Powers) and music by Andrew Lloyd Webber.  Based on Billy Wilder's Academy Award-winning 1950 film of the same title, the plot revolves around Norma Desmond, a faded star of the silent screen era, living in the past in her decaying mansion on the fabled Los Angeles street.  When young screenwriter Joe Gillis accidentally crosses her path, she sees in him an opportunity to make her comeback to the big screen.  Romance and tragedy follow. Some Like It Hot (subtitled Modern Jazz Performances of Songs featured in the Motion Picture starring Marilyn Monroe, Tony Curtis & Jack Lemmon Produced and Directed by Billy Wilder) is an album by guitarist Barney Kessel performing adaptations music from Billy Wilder's 1959 film "Some Like It Hot", recorded in 1959 and released on the Contemporary label. One, Two, Three is a 1961 American comedy film directed by Billy Wilder and written by Wilder and I. A. L. Diamond.  It is based on the 1929 Hungarian one-act play "Egy, kettő, három" by Ferenc Molnár, with a "plot borrowed partly from" "Ninotchka", a 1939 film co-written by Wilder.  The comedy features James Cagney, Horst Buchholz, Lilo Pulver, Pamela Tiffin, Arlene Francis, Leon Askin, Howard St. John, and others.  It would be Cagney's last film appearance until "Ragtime" in 1981, 20 years later.
Answer: Sunset Boulevard