Sheehan who willl lead Ireland in the absence of the injured Caelan Doris spoke to the media after Captain's Run in Sydney today, "I remember getting the call on day two of the celebrations of the URC and it didn’t faze me at all. I was more disappointed for Caelan at the time."
"I knew it wasn't great, his injury, so I kind of had it in the back of my head slightly that I need to be ready to go.
"It was just a quick call, like 30 seconds. 'Will you do it?’ And I was like, ‘Yeah, sure, I'll see you in Sydney’ because he (Andy Farrell) was on the flight ahead."
The squad arrived in Sydney last week and took a coupld of days to recover before ramping up the gears in preparation for the match.
Sheehan is also keen to stress the role of the leadership group in the squad, "We have a great group of leaders in the squad already, so it’s just a good chance for me to develop my own personal skills but also get a grip of the squad in a full month on tour, which has been nice.
"I think the prep has been good. I've enjoyed the build up to it. I think everyone's raring to go.
"It's been perfectly fine, it's probably trying to get away from thinking about it (being captain) all the time; how's the group feeling? Do you need to address anything, all this stuff.
"But this group is very well disciplined and take it extremely seriously every time they get a chance to put on this jersey."
"Obviously we have to wait and see tomorrow, but I'm fizzing to go and my head feels pretty clear and free, which is the way you want to be as a player.
"I think we wanted to hit the ground running. We're a very diligent group that preps very well.
"Trying to think back to the Six Nations, we hit the ground running in Portugal, we thought we had a great week's prep and we obviously didn't give the best version of ourselves on the day in that first game in France.
"That's been my focus on the last couple of weeks, just making sure that the lads are switched on and not overawed by detail,"