Fresh off one of the greatest grand-final performances in history, Walsh's star has risen further after a spellbinding Test debut in Australia's series-opening Ashes win.
Walsh enters the second Test in Everton as the most talked about rugby league player in England, after scoring two tries, breaking five tackles and running 243 metres in last week's win at Wembley.
The 23-year-old could cap off one of the finest seasons in recent memory if he secures a series win in the match that begins at 1.30am AEDT on Sunday.
Walsh has long been one of the most marketable men in rugby league, with celebrity status rivalling Benji Marshall and Sonny Bill Williams at their peak.
The Queensland superstar already has the most social media followers in rugby league on both Instagram and TikTok, with close to 1.1 million on the two platforms combined.
And while Parker isn't worried about the Kangaroos No.1's ability to handle the hype, he does fear it could one day lead to Walsh being lured into bigger pastures.
"My concern is that because he is of such a status and has such a cult following that he tries to go worldwide and bigger," Parker told AAP.Â
"In rugby league, it's just harnessed here in Australia and in the north of England. If you look at rugby union for example, that is worldwide.
"I've never seen anyone with that kind of following in it in my time. So it's whether he stays in the game for his whole entire career ... I hope he does."
The fears of the Broncos legend, who is an ambassador for the World Supercross event on the Gold Coast in November, come after a bold declaration from Graham Lowe.
New Zealand rugby league icon Lowe urged the All Blacks to make a play for Walsh by offering him $5 million a year.
Speaking following Brisbane's grand final win, the former coach and administrator labelled Walsh the best young player he'd ever seen and claimed he would bring an extra 10,000 people to games.
Walsh only signed a new five-season deal with the Broncos at the end of last year, keeping him with Brisbane until the end of 2029 on close to $1 million a season.
"I actually can't even forecast how big he is going to get," Parker said.
"If you're just looking purely on his talent, it's pretty obvious. But the status and the following and everything that goes with it is on a whole new level.
"I've had a fair bit to do with Reece and to watch him elevate himself in the grand final when Brisbane were under the pump and lost their No.6 and No.7.
"It's normally panic stations. But strangely enough it was quite calm given the fact Reece was doing what he was doing. He was terrific."
A win for Australia would ensure the Kangaroos win the Ashes for a 14th straight series, with a third Test still to play next week.
England look likely to debut AJ Brimson at fullback this weekend, with Jack Welsby dropped from their 19-man squad. John Bateman is also out with illness.
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