Heaslip has been appointed skipper for the tournament even though Brian O'Driscoll, who has filled the post on a permanent basis since 2004, is fit after recovering from an ankle injury.
"I'm still wet behind the ears so it's great, I'm buzzing. It's really exciting to come here," the Leinster number eight said.
"I've been feeling really giddy and haven't stopped smiling since I got here....maybe it's the double espresso from the early start.
"I found out about the captaincy last Wednesday evening. Declan gave me a call to go and see him.
"In I went and after a bit of chit chat he asked me to do the job and I nearly had to stop myself jumping across the table to kiss him, which would have made it really awkward in a room with just two guys!
"I was really proud and humbled by it all. There were all sorts of emotions flying around.
"I made the obligatory call to the parents. My dad straight away said 'fair play, you've been promoted, but I'm still colonel while you're major, so I'm pulling rank on you'. I said 'thanks dad, back to reality as usual'."