Christina Aguilera sings Falling In Love Again from 1930 in The Spirit

[theMan-Bat]

Christina Aguilera sings the classic Falling In Love Again with a contemporary sound in The Spirit. The song dates back to 1930, written by Frederick Hollander as a jazz ballad (it was the jazz age), with lyrics written by Sammy Lerner.
The song was originally sung, and popularized, by Marlene Dietrich in the film The Blue Angel (1930).
The song was covered by Billie Holiday (1940), Doris Day (1961), Sammy Davis Jr. (1962), and many others.
Here's Sammy's swing jazz version:

 

[Bubastis]

Like, she sings it for promotion for the movie or she's in the film singing that song?

 

[theMan-Bat]

Like, she sings it for promotion for the movie or she's in the film singing that song?

In the film.