How do I access a function in one class from another?

programming flash
1

I have a AS3 MP3 player. The player class controls the play and pause buttons. The playlist class loads the track names into a playlist from XML. In the playlist is a download button. When the download button is pressed, I want the player to pause. I thought I could just _player.pause(); from the playlist class but it doesnt work.

How do I access the function in the MP3 player class from the playlist class?

Thanks!
Rich