From fat club to the NRL’s most prolific try-scorer – Robert Jennings’ rise and rise is shaping as one of best stories of South Sydney’s stellar NRL season.

Jennings on Saturday became the surprise leader on the NRL’s try-scorer list after bagging his third hat-trick of the season, in the Rabbitohs 24-6 win at ANZ Stadium.

While Jennings has been the beneficiary of South’s in-form left side, he has established himself as one of the game’s best finishers this year.

A case in point was his third and final four-pointer on Saturday when it appeared little was on before the 22-year-old created something out of nothing.

“He’s been a real big improver for us this year, there’s no doubt about that,” Rabbitohs coach Anthony Seibold said.

“He’s scored a heap so far. Even his carries out of the backfield for us really creates momentum. I’ve loved the way he’s applied himself this year.”

Jennings has now bagged 16 tries in 15 games – moving him ahead of Warriors winger David Fusitu’a in the try-scoring stakes.

And while the western Sydney product – the younger brother of Parramatta pair Michael and George – is reaping the benefits of his hard work, Seibold revealed Jennings was given a rocket after turning up to pre-season training overweight.

Jennings has kept Richie Kennar and Hymel Hunt out of the starting side this year but Seibold said he had been forced to come from a long way back in the pack.

“He turned up at pre-season training about eight kilos overweight,” Seibold said.

“I kicked him up the backside and since then he’s had to apply himself.

“He’s been a lot more consistent with the way he trains and he’s been a lot more consistent with his preparation.

“He’s probably never going to die of stress Jenko, he’s a pretty relaxed sort of guy. But he’s worked hard, he’s had to because I wasn’t happy with the way he turned up at pre-season day one.

“He was coming from a long way back. But something just clicked for him and he’s carried that form.”