Iggy Azalea says she has been "fangirling" over Britney Spears' contribution to their new duet.

The pop princess and the Australian rapper recently teamed up for the track 'Pretty Girls'.

It received its debut a few days ago and it seems Azalea is still overawed by the collaboration.

She posted on Twitter on Monday (May 4): "To be honest im just over here acting like a total fan girl for britneys vocals on this song.

"Cant. stop. listening. So classically britney [sic]."

Spears responded to the tweet by saying: "To be honest I'm trying to get that rap down! You killed it girl!! So happy we did this!!!"

'Pretty Girls' meanwhile is available to buy now.

Follow us: @Pressparty on Twitter / Pressparty on Facebook.

Listen to the duet below: