The 'Greatest Showman' actor - who won the accolade in 2008, two years before the 'Deadpool' star - warned the 40-year-old singer he needed to "fall in with the right crowd" now he has joined the "very, very prestigious" group to have been given the title and couldn't resist taking a swipe at his friend as he did so.
Hugh shared a video on Instagram of himself and Ryan looking at the 2008 Sexiest Man Alive cover and captioned the clip: "Dear John. Massive congrats on joining this very very prestigious group. 99% of the time, People Magazine gets it right. Such as Blake, DJ, etc ...
"But a word of caution. There is the 1%. Exhibit A. It's important that you fall in with the right crowd. Enjoy your reign. Love Hugh.(sic)"
But the 'All of Me' hitmaker claimed he was left confused by the advice.
He commented: "Wait so you're the 99 and Reynolds is the 1? Or vice versa? (sic)"
Ryan and Hugh often take digs at one another while seemingly issuing compliments.
In September, the 'Wolverine' star was honoured with Australia's Companion of the Order.
And in response, his pal wrote: "Receiving the Order of Australia is a HUGE deal. And despite what I tell anyone who'll listen, Hugh Jackman is one of the finest, kindest, hardest working, generous and most talented people I've had the privilege to call my friend. There's nobody better.
"None of this changes the unfortunate fact he's a complete b*****d. (sic)"
And the 51-year-old actor joked he kept trying not to ignore too many of Ryan's phonecalls about a potential 'Deadpool' and 'Wolverine' crossover movie.
He quipped: "If [Ryan] has his way, it's literally every day. I answer every fourth day because it would be embarrassing if I never answered him."
Ahead of his tour earlier this year, Hugh claimed he'd turned down an offer from his 43-year-old pal to join him on stage.
He said: "He's like, 'I've been working on my dancing.' I'm like, 'Dude!'"