The drama focuses on a young attorney called Lily.
She teams up with an angel who has recently become a human and the pair work on cases together.
Deadline says that Aldridge has now signed up to play the former angel, Dashiel.
Aldridge has appeared in British dramas The Devil's Whore, Lewis and Toast and recently starred in Lark Rise to Candleford.
Heavenly is being written by Richard Hatem, who has previously worked on shows including The Gates, Supernatural and Tru Calling.