Code Sports and the Sydney Morning Herald are reporting that Jack died of an accidental overdose.
Jack Waugh (left) with his dad Phil and brother Charlie. Photo / @charliewaughhh
His younger brother Charlie posted a tribute on social media this week.
“To my big brother. I love you more than words could ever explain,” Charlie wrote.
“You helped me grow into the person I am today, always looked out for me and protected me when I needed it most. I’ll carry everything you taught me for the rest of my life.
“I know you’ll be looking over me from wherever you are, and I know you’ll always be rooting for me. I hope I can make you proud.
“Rest easy Jack, I love you, always and forever.”
Born prematurely, Jack spent the first three months of his life in intensive care, with his father becoming an advocate for the Miracle Babies Foundation, a charity supporting families of premature and sick newborns.
“[Jack was born] 1040 grams, and then, as we know, all babies lose weight after birth so he went down to 970 grams at his lowest,” Phil said in a 2019 interview with 2GB.
“So quite confronting when you have hopes of a healthy newborn, and they come 13 weeks early.
“And at that weight, it’s quite terrifying for any parent.
“We were in intensive care for 12 weeks, and obviously you just don’t know what the outcome’s going to be.
“But also not just the short-term outcome but also the long-term effects.
“And we’ve been particularly lucky with our son Jack, and he’s got no issues today but certainly others aren’t as lucky as what we are.”
The former Waratahs and Wallabies flanker has two other children from a second marriage.