Wandabaa is also on her second trip to Queensland and was beaten just over one length last start when an eye-catching second in The Hunter.
Both will be ridden by Andrew Mallyon, who has forged a strong partnership with the Lees stable since relocating from Victoria two years ago.
Mallyon has had 127 rides for the stable for 36 wins and 26 placings.
Gem Song is raced in a syndicate which includes Lees Racing and Australian Bloodstock and is a winner of six of his 19 eight starts.
His best wins were at Group 3 level in the Eskimo Prince (1200m) at Warwick Farm and Gunsynd Classic at Eagle Farm in 2019 before claiming this year's Newmarket Handicap at Newcastle in March.
Gold Coast trainer Mel Eggleston is in charge of Lee's Queensland base and believes both will appreciate a heavy track.
"They've both got live chances," Eggleston said.
"Wandabaa loves heavy tracks and the wet will help Gem Song a lot.
"Gem Song was a bit short of match fitness last start and he's come on a lot since his last run.
"I looked after him when he won the Gunsynd Classic as a three-year-old and then he ran fourth in the Doomben Cup.
"He looked like being a super star at one stage but when he went back home, he broke down."
Five-year-old mare, Wandabaa, had started 28 times for seven wins and 13 placings and will be chasing her first Stakes win to boost her broodmare value.
"The wetter the better for her but she gets back and needs speed on in her races," Eggleston said.
"She'll need a bit of luck but she's got a nice soft draw."