Do it with a smile on your face… you’re excited about it, he should be as well! You’ll find that body language, tone of voice and so on do a lot to people and how they receive/perceive news… if you approach him with a solemn tone, you’ll make him feel like you’re running away or leaving because “you have to”: He’ll feel sorry for something he may not know of.
If he’s the type of guy I think he is, he’ll probably keep it real short and to the point. Once he’s heard all the needs to, he’ll want to leave the room probably… he doesn’t wanna show any form of “soft” side to you or anyone if he can manage it, he’ll see it like a sign of weakness and he knows that he has to maintain the tough man facade.
Also, don’t tell him that you approached him last… that’ll make him feel less important to you.