He's five weeks off his Knights debut but young Kalyn Ponga's athletic ability has fans more worried than assured.

The 19-year-old's latest Instagram post has sparked a flurry of nervous comments from Newcastle followers who couldn't help laying on the mum-like advice.

Not that you could blame them; the new recruit's backflip from a roof into the pool below would have anyone feeling a little jumpy.

"Good to see you enjoying yourself Kalyn but you need to remember your committed to the Knights so you need to tone down the acrobatics," one fan, Ryan Marshall, cautioned.

"As a long-time member and I speak for all fans and members we have waited a long time to be this excited about an upcoming season and we want you to be a massive part of that."

Another, Tony Lorello, added: "Footy players not rocket scientists."

For all the advice - and joking around - the stunt didn't attract too much negativity, with a few urging Ponga to enjoy his life outside of footy.

The Knights beat out four other clubs jostling to attract the young fullback when he went onto the open market in 2016, signing him to a four-year deal thought to be worth $600,000 a season.

And with just over a month to go until round one, Ponga would be forgiven for letting off a little of that steam.