Tyrone star Colm Cavanagh is expecting "war" in the Kingdom as Killarney prepares to host a record crowd for an SFC qualifier outside of Dublin.
With huge interest being generated in what many see as a grudge match between the two long-standing rivals, Kerry say they're planning for a crowd of at least 25,000 -- a figure that has never been reached for a back-door match outside of Croke Park.
"Judging by the Kerry crowd that went to Mullingar, the number of visitors to the area at present and the Tyrone crowd that could travel, we're preparing for 25,000," said O'Sullivan.
Kerry have lost their last three championship meetings against Mickey Harte's men, and while O'Sullivan insists the clash at Fitzgerald Stadium is about "getting to the next round of the qualifiers and not about revenge", the message from Tyrone is slightly different.
As two of the game's giants lock horns, midfielder Cavanagh is predicting a "war" in the battle for championship survival.
"This is Kerry. They may have had a bit of a rough patch, but they are still one of the best teams in the country, and we will have to be up for it," Cavanagh declared. "It's going to be a war, a very tough game for us, especially with Kerry having home advantage. Kerry are the team that everybody wanted to avoid.
"There's no doubt about it, it's going to be a very tough game for us, but we just have to get on with it."
And the Moy clubman sees home advantage as a massive help for Jack O'Connor's side.
"It is a huge advantage -- there will be a big Kerry crowd there, getting behind their team. It's going to be an intimidating atmosphere, but that's part of the challenge for us and we just have to deal with it," he said.
If the Killarney expectations proved correct, it will mean another cash bonanza weekend for the GAA as the 100,000 attendance mark will be surpassed for the second time this summer, generating in excess of €2m in gate receipts.
The cumulative attendances were just over the six-figure mark last weekend, but with three other qualifier games slated for Saturday, this will be by far the busiest weekend of the football championship.