AFL Grand Final 30 Sep 2006
Brian, along with fellow Countdown Spectacular artists Daryl Braithwaite, Joe Camilleri, Shane Howard, John Paul Young and Sean from The Models, performed their hits (Brian sung Work) and footy song Up There Cazaly, as part of the pre game entertainent at the AFL Grand Final. They then returned to the field with the West Coast Eagles and the Sydney Swans to sing the national anthem. (Updated 7 Oct 06.)
Except from an article about the pre game entertainment in The Age.

Eyes firmly on the ball by Marieke Hardy
October 5, 2006

The entire pre-game broadcast was saved - nay, raised to giddy, unsurpassable heights - by the jaunty appearance of Australian rock's own Iggy Pop, Brian Mannix.

Any man over 40 wearing a pair of eye-wateringly tight black jeans on national television and actually pulling it off deserves not only a standing ovation but possibly an open invitation to remain in the centre square for the remainder of the game. I can't say I've seen much of Brian since his Uncanny X-Men days, although after witnessing his complete upstaging of the archaic '70s Rock Dogs wheeled out by the AFL to entertain us with a medley of lip-sync, I'm starting a one-woman campaign to revive his career.
Daryl Braithwaite seemed terrified throughout the pre-game performance as he inched his microphone as far from Mannix's sexy groin-based air-guitar stylings as possible, which was an altogether pleasing sight. Someone give the man a Batmobile and parade him around with the hall-of-famers next year.