The Giants forward is expected to announce his retirement at a press conference on Thursday morning, ending months of speculation about his future.

The 34-year-old's impending retirement has been widely anticipated but it will nevertheless be a sad day for the showman's legion of fans.

The grand final motorcade will be chock-full of stars with Johnson joining the likes of Nick Riewoldt, Luke Hodge, Sam Mitchell, Matt Priddis, Scott Thompson, Jobe Watson and Matthew Boyd to draw the curtains on their distinguished careers.

Johnson, however, will have designs on being part of the main event with his Giants leading fancies for this year's premiership.

Although his glory years were long gone, Johnson has still given Giants fans plenty of highlights in his two seasons in western Sydney, not the least his last-gasp winner against Collingwood earlier this year.

He kicked 43 goals last year, behind Jeremy Cameron and Toby Greene, and managed a top 10 finish in the star-studded club's best and fairest count.

One of the most entertaining players of his time, Johnson was a problem child early but blossomed to become a three-time premiership player with Geelong.

He won the 2007 Norm Smith Medal and collected three All Australian jumpers in a 253-game career for the Cats before crossing to the Giants at the end of 2015.

Geelong fans will have their chance to farewell Johnson in round 23 when the Giants head to Simonds Stadium.