ireland v england, live tomorrow rte2/bbc1 (ko 3.0)
Forget all the small talk about this being just another game. It isn't to Jack McGrath (inset).
"It's my biggest start and my biggest game ever. I'm really looking forward to it now," he said.
"I don't want to get too excited, too early. It's definitely something I will remember for the rest of my life and, hopefully, it will be a good one to remember."
Will the Leinster loose-head also recall this as the day he legitimately moved into the number one slot ahead of Cian Healy?
"It is great to get the nod and still brilliant to have Cian back in the squad. He has played two 40 minutes in the last two weeks and he has done really well."
Ireland will need every ounce of energy McGrath and Healy can muster in a side showing just one change from France as Jordi Murphy materialises at number eight for the injured Jamie Heaslip.
The divvying up of duties between McGrath and Healy is just a personal duel to be fought out over the next half-dozen years and more.
For the moment, McGrath will have to focus on what is in front of him, not who is behind.
England have countered Ireland's aerial bombardment by bringing in Alex Goode for the injured Mike Brown and Jack Nowell for the dropped Jonny May.
"It's going to be one of our hardest tests for a long time," he said.
"Yeah, definitely. They're probably the favourites for the competition. They're coming over here to our patch. We haven't beaten them in four years," he said. "In our own stadium, the crowd is going to be baying for blood. We really have to go out there and show we want to retain our championship."
Ireland: R Kearney; T Bowe, J Payne, R Henshaw, S Zebo; J Sexton, C Murray; J McGrath, R Best, M Ross, D Toner, P O'Connell (capt), P O'Mahony, S O'Brien, J Murphy.
England: A Goode; A Watson, J Joseph, L Burrell, J Nowell; G Ford, B Youngs; J Marler, D Hartley, D Cole, D Attwood, G Kruis, J Haskell, C Robshaw (capt), B Vunipola.