In a new interview with MTV, Justin Timberlake briefly commented on working with Madonna:

MTV: And you're working with Madonna?

Timberlake: We did work in the studio together, we came up with some really cool stuff. I don't know what else to tell you except that you'll hear it soon.

MTV: What's the name of the song?

Timberlake: I don't want to tell you that, because she'll either kill me or she'll have me kill you. And I think we have enough celebrities going to jail. [He laughs.]

Source: Larry Carroll, MTV