The actor is to play Chris, the former partner of lapdancer Cheryl Gray (Holly Quin-Ankrah), according to the soap's official website.
It emerges that Chris and Cheryl share a son, Russ. However, things take a turn for the worse when Chris meets Cheryl's current boyfriend Lloyd (Craig Charles).
Thorp, who played Woody in Casualty, has also appeared in Holby City and Doctor Who.
He is expected to turn up in the Street later this summer.