Which film was the first to feature the song 'White Christmas'?

Holiday Inn is a 1942 American musical film directed by Mark Sandrich and starring Bing Crosby and Fred Astaire. With music by Irving Berlin, the composer wrote twelve songs specifically for the film, the best known being "White Christmas". The film features the complete reuse of "Easter Parade", written by Berlin for the 1933 Broadway revue As Thousands Cheer. The film's choreography was by Danny Dare.

The film received a 1943 Academy Award for Best Original Song (Irving Berlin for "White Christmas"), as well as Academy Award nominations for Best Score (Robert Emmett Dolan) and Best Original Story (Irving Berlin).

The song that would become "White Christmas" was conceived by Berlin on the set of the film Top Hat in 1935. He hummed the melody to Astaire and the film's director Mark Sandrich as a song possibility for a future Astaire-Ginger Rogers vehicle. Astaire loved the tune, but Sandrich passed on it. Berlin's assignment for Paramount was to write a song about each of the major holidays of the year. He found that writing a song about Christmas was the most challenging, due to his Jewish upbringing.