Horwill was a promising schoolboy player 11 years ago when the Lions visited Brisbane for the first Test against the then World Champion Wallabies and he will never forget what he saw on that incredible night.
"I remember '01 when the Lions came to Brisbane. I remember the fans in Brisbane in particular," said Horwill.
"The Red Army took over The Gabba. There was more red in the crowd than gold and that was something we'd never seen before.
"I just remember the overwhelming support they had - it's something I'll always remember.
"I was still at high school then but it sticks in your mind pretty clearly just how loud the Lions supporters were. They're great fans and there was nothing untoward about them and the Aussie fans - it was just good clean fun and good banter."
The Lions enjoyed amazing support the last time they visited Australia
With the Lions' next trip to Australia now less than 10 months away, Horwill is hoping for a similar situation next summer.
While he doesn't wish to see British and Irish fans outnumber their Aussie counterparts, he is keen to welcome thousands upon thousands of Lions followers to his homeland for what should be yet another wonderful occasion.
And the star second row, who wants to face the Lions with both the Wallabies and the Reds in 2013, believes the presence of vast numbers of travelling fans will inspire Australians into action, just as they did last time out.
"We're speaking of unique things: you expect a lot of Lions fans to come to Australia and that adds to the spectacle of a Lions tour," added Horwill.
"We hope to see a lot of them down here. We're hoping there are more Reds and Wallabies fans than Lions supporters but they definitely add to the atmosphere.
"It does have a big impact. You never like to be outshone as a supporter when a touring team come over.
"We hope that our fans will take it to the Lions fans. It's an exciting opportunity for the Australian fans as well as the players to see such a traditional and well-respected side come over and play a number of games around the country.
"We're very lucky in Australia, and in where I'm from in Brisbane, that our fans have got right behind us at provincial and national level. Because of what happened on the 2001 tour, the fans understand that they will have to get right behind our group."
James Horwill was handed the Wallaby captaincy by Robbie Deans
Horwill would love to experience such support next summer but he hasn't been named in the Wallabies 30-man squad for the forthcoming Rugby Championship.
A serious injury ruled him out of the four June Tests with Scotland and Wales and no date has yet been set for his return to action.
The 27-year-old ruptured one of the four hamstring tendons in his right leg back in May, leading critics to question whether he would ever be able to hit the heights of top-level rugby again.
But although he admits it's a frustrating time for him personally at the moment, he insists there is no danger of him not recapturing his best form prior to the arrival of the Lions.
"I know I can come through the other side," added Horwill, who is still desperate for the Wallabies to succeed in the inaugural Rugby Championship campaign even though he will be limited to a behind-the-scenes role as his rivals press their own claims for his Test place.
"I've had two major injuries before when people told me I could never be the same - my knee reconstruction and a foot injury Tim Horan had, which he said forced him to end his career, so I know I can get through that.
"It gives me belief. I can trust the doctors and medical staff and the rehabilitation.
"It's never good having any time off… I love playing. Robbie (Deans, Wallaby coach) has just told me to get the hammy right. I can only control what I can control. I'm focusing on trying to get myself right - when I come back and am ready to play, we'll have to see.
"I want the Wallabies to win. I want to see us hold up the Rugby Championship trophy and the Bledisloe Cup. There is no part of me that wishes failure on anybody.
"I want guys to succeed in the Wallabies jersey, and if I can help those guys along the way I'll really enjoy that."