- What kind of an act is it?
- It's a sister act.

5 seconds sound clip from the White Christmas (1954) movie soundboard.

You can hear this line at 00:17:45 in the Blu-ray version of the movie.

Quote context

[...]

- Forty-five minutes going to be enough?

- If I need any more, I'll tell you.

- Come in!

- Your railroad tickets, sir. Drawing Room A, Car 207.

- Thanks.

- Grab those, will you, Phil?

- Here.

- We'll go right over to the station from Novello's after we audition this act.

- What kind of an act is it?

- It's a sister act.

- We don't need any sister act. What are we wasting time for?

- Well, I got a letter from Benny Haynes. They're his sisters. Do you remember Benny Haynes, the old mess sergeant?

- Freckle-Face Haynes, the dog-faced boy?

- That's the kid. Yeah.

- He's got sisters?

- Claims he's got them.

[...]