Marcus (played by Charlie Condou) and his friend Maria Connor (Samia Ghadie) - whose relationship has recently been complicated by a surprise kiss - will play host to Ron and Janet Dent when the pair arrive on Christmas Day.
A post on the official Coronation Street website confirms that Ron will be played by Blake's 7 star Stephen Greif, who has also appeared in Birds of a Feather and Tales of the Unexpected.
Marcus's mother Janet will be played by Linda Clark, whose previous credits include Doctor Who, Emmerdale and That Peter Kay Thing.
Christmas Day marks the first time Ron and Janet will have met Maria and encountered their openly gay son's developing relationship with the hairdresser.
Some 7.8m people tuned in to watch Marcus and Maria's shock romance begin to blossom earlier this month. The episode gave the soap its highest audience figures for the Friday slot since the spring.
Coronation Street continues this Monday, October 29 at 7.30pm on ITV1. Get the Inside Soap magazine on your iPhone or iPad