Question: Who was a three-time Olympic Champion, that starred in the musical film "Sun Valley Serenade"?

Context paragraphs:
Sun Valley Serenade: Sun Valley Serenade is a 1941 musical film starring Sonja Henie, John Payne, Glenn Miller, Milton Berle, and Lynn Bari.  It features the Glenn Miller Orchestra as well as dancing by the Nicholas Brothers and Dorothy Dandridge, performing "Chattanooga Choo Choo", which was nominated for an Academy Award for Best Song, was inducted into the Grammy Hall of Fame in 1996, and was awarded the first Gold Record for sales of 1.2 million.

Fayard Nicholas: Fayard Antonio Nicholas (October 20, 1914 – January 24, 2006) was an American choreographer, dancer and actor.  He and his younger brother Harold Nicholas made up the Nicholas Brothers tap-dance duo, who starred in the MGM musicals "An All-Colored Vaudeville Show" (1935), "Stormy Weather" (1943), "The Pirate" (1948), and "Hard Four" (2007).  The Nicholas brothers also starred in the 20th Century-Fox musicals "Down Argentine Way" (1940), "Sun Valley Serenade" (1941), and "Orchestra Wives" (1942).

It Happened in Sun Valley: "It Happened in Sun Valley" is a 1941 song composed by Harry Warren and with lyrics by Mack Gordon.  It was recorded and featured by Glenn Miller and his Orchestra in the movie "Sun Valley Serenade".

Sonja Henie: Sonja Henie (8 April 1912 – 12 October 1969) was a Norwegian figure skater and film star.  She was a three-time Olympic Champion (1928, 1932, 1936) in Ladies' Singles, a ten-time World Champion (1927–1936) and a six-time European Champion (1931–1936).  Henie won more Olympic and World titles than any other ladies' figure skater.  At the height of her acting career, she was one of the highest paid stars in Hollywood and starred in a series of box-office hits, including "Thin Ice" (1937), "My Lucky Star" (1938), "Second Fiddle" (1939) and "Sun Valley Serenade" (1941).

Gretchen Fraser: Gretchen Kunigk Fraser (February 11, 1919 – February 17, 1994) was an alpine ski racer.  She was the first American to win an Olympic gold medal in skiing.  She was also the skiing stand-in for ice skater Sonja Henie in the movies "Thin Ice" (1937) and "Sun Valley Serenade" (1941).

Emil Newman: Emil Newman (January 20, 1911 – August 30, 1984) was an American music director and conductor who worked on more than 200 films and TV shows.  He was nominated for an Oscar for his musical direction on the classic "Sun Valley Serenade" (1941).

At Last: "At Last" is a 1941 song written by Mack Gordon and Harry Warren for the musical film "Sun Valley Serenade" (1941), starring Sonja Henie and John Payne.  Prior to release, it was performed in the film by Glenn Miller and his orchestra, with vocal by John Payne and Lynn Bari, dubbed by Pat Friday.  Studio head Darryl Zanuck reportedly said, “There are too many big ones in this.  Let’s save one for the next.”  The “At Last” vocal by Payne and Bari was thus deleted, although instrumental versions remained in the film, including in the Black Ice Ballet finale.

Sun Valley Opera House: The Sun Valley Opera House was built in 1937 in Sun Valley, Idaho, as a movie theater.  The picturesque Opera House has a 344-seat capacity and a state-of-the-art sound system (installed in 1999).  It is the site for special events and as well as nightly showing of first-run movies.  It is located in the Sun Valley Village, near the Sun Valley Lodge and Sun Valley Inn.

Chattanooga Choo Choo (film): Chattanooga Choo Choo is a 1984 comedy film starring Barbara Eden, George Kennedy, Melissa Sue Anderson and Joe Namath, directed by Bruce Bilson which was released on May 25, 1984.  The film is inspired by the popular 1941 song "Chattanooga Choo Choo" originally recorded by the Glenn Miller Orchestra and featured in the 20th Century Fox film "Sun Valley Serenade".

Sun Valley National High School: Sun Valley National High School or SVNHS (formerly known as Dr. Arcadio Santos National High School - Sun Valley Annex) (Filipino: Mataas na Paaralang Pambansa ng Sun Valley) is a public national high school in Parañaque, located at Elizabeth Ave., Sta.  Ana Drive, Brgy.  Sun Valley.  It is under the administration of the local government of Parañaque City and is recognized by the Department of Education.  It offers public education for the residents of Brgy.  Sun Valley as well as for those living near it.  The current principal/officer-in-charge is Dr. Leonisa D. Romano, Secondary School Principal I.  At present, it has approximately 2, 222 students from Grade 7 to Grade 10

Supporting paragraphs: At Last Sonja Henie
Answer: Sonja Henie