TIM Cahill says playing at The Den again will be a special moment in his career.
The midfielder is set to feature in the Australia team that takes on Ecuador on Wednesday night in an international friendly.
And Cahill, who scored 52 goals in 217 appearances for the Lions between 1998 and 2004, admits returning to SE16 will be an "emotional" experience.
"This is where it all started," he said, speaking at a pre-match press conference.
"I learned my trade here, played with some great players and it has definitely helped define who I am as a footballer today.
"I still have the same traits as I did when I was 16 purely because of what I learned from the players I played with, the fans and the club.
"When I come back and see the same people working for the club, people who love the club, it's something special."
Cahill, who currently plays for the New York Red Bulls in the MLS, added that the backing he has received from Millwall fans since leaving the club has been phenomenal.
"I'm very active on Twitter and Instagram – their support has been unbelievable," he said.
"Hopefully I can get some game time tomorrow night because it will be a special occasion. It's a weird feeling being here again.
"If you can't play in front of Millwall supporters, then you should stop playing football. They are the most passionate fans in the world. They live for football.
"They go to work during the week for their team and The Den is their outlet on a Saturday.
"When you get to know that football is a way of life for your fans, you know what it is to be a Millwall player."
"Playing in front of these fans is the best feeling ever – I've been on the other end, when the fans haven't been happy, but if you can play at Millwall, you can play anywhere in the world.
"That's the greatest thing I can say because the fans have been great to me. I've had some of my greatest moments in football here."
Cahill will become the Socceroos' all-time leading goalscorer if he finds the target against the South American side.
"I was speaking to someone really close to me last week about how the stars can align like this," he said.
"This is where it all started, so to score tomorrow, if I play, will be a very special moment in my career. Millwall, along with Everton, is the place I call home.
"It's great that the game is at The Den and for me to have that sentimental moment, but for us as a team, we're in a new era and breeding a lot of youngsters.
"I'm the oldest player in the squad and it's all about preparing for the World Cup."