The uncapped all-rounder, who recently won the County Championship with Durham, was named in the 16-man party on Monday.
"It's pretty special," Stokes told the England and Wales Cricket Board's official website. "It's the first time I've won the Championship and my first time as part of an Ashes team and they've both happened together.
"It's been a hectic week for myself, and for everyone involved with Durham, but it's been absolutely fantastic. Three or four weeks ago it was something I wasn't even thinking of.
"Geoff Miller rang me on Sunday morning and, to be honest, I'm pretty shocked and surprised that I was in the squad."
The first Ashes Test between England and Australia gets underway in Brisbane on November 21.