Nick Fury with Ally in play already

[ViralAgent]

Hi all, this question came up in my game of Marvel Munchkin tonight:

I have Iron Man (an Ally) in play. I want to play Nick Fury from my hand, who states that I may have an additional ally. Do I have to discard Iron Man to play Nick Fury, or does Nick Furies ability come into effect at the same time he does, allowing me to play him as his own "additional ally"

If you need any more info to understand my question, please let me know.

Thanks.