The heavyweight pair officially launched the bout at the WIN Entertainment Centre on Tuesday and didn't see eye-to-eye, figuratively or literally, on many things but both called for rigorous drug testing measures before and after their showdown.

The topic of PED's has naturally arisen ahead of the bout given the pair's respective histories. Gallen became the reluctant face of the Sharks ASADA investigation over the club supplements program in the latter part of his NRL career, while Browne had his WBA world title stripped after returning a positive test for clenbuterol following his win over Ruslan Chagaev in Chechnya in 2016.

The finding was subsequently overturned and the title re-instated but the spectre has remained for Australia's only world heavyweight champion, with Gallen more than willing trade barbs on the issue on Tuesday.

"I saw whim yesterday and I didn't know whether to give him a bra or not, he's developing bitch tits there," Gallen said.

"My missus actually saw him and actually said 'should I give him a bra?' I said 'darlin' they're a probably a bit big for you those bitch tits'. Maybe all the supplements over the years are starting to take effect.

"Lucas told me [on Monday] he's only ever been tested when he's fought overseas, he's never been tested in Australia. It's four or five fights overseas and he's tested positive twice, that's a fair strike rate.

"I asked the Rose boys [promotors Matt and George] if I could be tested today randomly throughout the course of the preparation and after the fight. I'm not sure what's happening there, it's up to them, but I want it to be tested as much as we possibly can."

Read more: Browne vows no second chances for Gallen

Though Browne admits he was careless in using an over the counter supplement that triggered a second doping violation eight months later, he maintains a clear conscience in regards to his world title victory in March 2016.

"Since all the drug scandal thing with Chagaev, I've been part of the WBC clean boxing program so I have to tell them where I'm going to be at all times because they can rock up at any time and test me so I've got no problem with that," Browne said.

"The fact of the matter is [before the Chagaev fight] I paid for the [VADA] testing myself, I was tested three days before the fight in Chechnya and was completely clear. Why would I take clenbuterol knowing that I'm going to be tested because I've paid for it myself?

"Nothing ever made sense, but unfortunately you just can't tell people that. People just stick with it and call me a drug cheat instead of accepting the fact that I was cleared and I've got the belt sitting at home. I've got a clear conscience completely, the belt's at home, so I'm happy.

"I love the fact there will be testing [for this fight], I think it's great for Australian boxing as well to show they are clean fighters fighting in Australia. I'm all for that."

The drug testing call wasn't the only salvo from Gallen, who labeled Browne's 29-2 record "padded" and questioned the legitimacy of his WBA title. Browne said none of it came as a surprise and vowed to do the bulk of his talking in the ring.

Read more: Gallen not fazed by 'part-time' boxing critics

"I realise he's got to build the fight up and he's the A-side of this one from the point of view of putting bums on seats. It's his lane, I'll just let him do his thing and I'm just going to jump along with it.

"I realise it's going to happen but, no matter what is said at any point in time, he will have to stand across from me and deal with me in the ring. He can say whatever he likes, come April 21st he's going to feel me."