England hooker Connie Powell will join Harlequins from Premier 15s rivals Gloucester-Hartpury for next season.
The 22-year-old has won nine caps for the Red Roses and was part of the England squad at the last World Cup.
Powell, who made her Gloucester debut in 2018, has featured in England squads in the past two Six Nations.
"Connie is a highly talented Test hooker who will add firepower and depth to our front row," Harlequins head coach Amy Turner told the club website.
"She has gained valuable experience at Test level and will be an exciting addition to our squad as we continue to strengthen our programme heading into next season."