Moloney spent eight years with Melbourne, playing 122 games, but left via free agency at the end of last season.
The match will also double as his 150th career outing.
Moloney has been a solid contributor in a poor first month for the 1-3 Lions, averaging 22.5 disposals per game.
"I'm really looking forward to it. That was the first game I looked for in the fixture, to see when we're playing Melbourne," Moloney said.
"I'm proud of what I've done at the footy club but I'm a Brisbane Lion now and hopefully we can get a win and kick-start our season."
Moloney is still best mates with Demons Colin Sylvia and Mark Jamar and regularly talks with Nathan Jones and Aaron Davey.
He said watching Melbourne suffer through the opening rounds of the season was not easy.
"I barracked for Melbourne my whole life - not when I was at Geelong - but when I was a kid," he said.
"I got to play for the club I barracked for and to run out at the MCG, it was what I dreamt of.
"Seeing your club in that situation, I was concerned and I spoke to a few people about it because I was concerned. It's out of my control now and I'm enjoying my time in Brisbane and want to win some games at the footy club and get some success.
"I'll be doing everything I can to get a win for the Brisbane Lions."
Last weekend it was Bomber Brendon Goddard's turn to play his former team when he lined up against St Kilda.
His emotional post-match interview got plenty of coverage, and Moloney said he had little idea how he'd react at the Gabba on Sunday.
"I'm not 100 per cent sure. It was an interesting one with BJ (Goddard). We're not robots and do show emotion at times. I thought it was good," he said.
"Until I actually play against the boys, I'm not sure."
Michael Whiting covers Brisbane Lions news for AFL.com.au. Follow him on Twitter: @AFL_mikewhiting
