Fletcher, who is a big fan of the sport, claimed it was a "once in a lifetime" chance and that he was looking forward to competing on the pitch.
"I suggested I’d like to play in the game when it was announced but didn’t think Scully would then make it become reality!" said the soap star.
"It’s a once in a lifetime opportunity for me to take the field for such a high profile match in benefit of a legend like Paul Sculthorpe.
"Hopefully the fans will come along in their thousands for what will be a great occasion and support Paul, who has put so much into St Helens and rugby league as a sport for more than 10 years."
The match takes place at St Helens' Knowsley Road ground on February 2.
Rugby star Sculthorpe commented: "I’d like to thank Kelvin for taking the time out of his schedule. I’m sure he’ll enjoy his time on the pitch for Saints and it will be a day to remember for both of us."
Soap Scoop
Home and Away relationship twists - PicsWe take an in-pictures look at next week's Home and Away episodes.
Soaps Interviews
Emmerdale star talks John death aftermathWe chat to Emmerdale's Adam Thomas about John's death and more.
Soap Ratings
'Emmerdale' John, Moira plot takes 7.7mEmmerdale continues to perform strongly on Wednesday evening.
Reality Bites
'Big Fat Gypsy Weddings' returns: ReviewReality Bites's verdict on the return of Big Fat Gypsy Weddings.
