Everyone says it’s harder to retain a title than win it in the first place but the Royal Navy are looking to spoil the Army’s party this Saturday at Twickenham.
Tensions are building ahead of the 100th fixture between the two sides - the Navy narrowly lost to the RAF 16-14, whereas the Army beat the air force 35-14 last week.
The men in red are favourites for the win - the Navy need to beat them by 12 points to have a chance of defending their title from 2016.
Ash Coates, the Royal Navy Rugby head coach, said:
"We've just got to remain positive, do everything as we do (...) Our success is build around the togetherness, we're staying in the boat as a group"
Among many VIP guests will be Prince Harry, who will attend the match as Patron of the Invictus Games Foundation, the official charity for the event.
Speaking to his friend and comrade Dave Henson MBE, he said he has to be "to be fairly impartial" despite his Army past:
Dave Henson told Harry:
"You and I have talked about the Armed Forces being a family, it's never truer a display of that than when you get to Army/Navy."
Prince Harry will be joined on the day by competitors from the 2014 and 2016 Invictus Games, as well as some of those hoping to be selected for the third Invictus Games in Toronto.
You can watch live coverage of the Army vs. Royal Navy clash live on Forces TV (Sky channel 264, Virgin 277 and Freesat 165, on Saturday 29 April from 14:50 BST: