Robert Downey Jr. was announced in the cast for Hulk and he spoke about it in press interviews leading up to Iron Man.
The rumours are regarding the cameo and I didn't give anything away? Did I? In fact during Marvel's operating profit results they gave details and named specific characters that would be showing up - including the cameo.
That is why I didn't include spoiler tags as I thought it was open, public knowledge. Sorry about that.