Merchant's departure was announced on 29 April 2010 and Clarke's casting was confirmed on .
She was part of the initial starring cast and remains a member of the starring cast for the second, third, fourth, fifth, sixth, seventh and eighth seasons.
Mail Online has contacted their representatives for comment.
The supposed romance marks Abi's first since her upsetting split from Rob, who she separated from last year.
She played the lead as Nurse Verena, in the film Voice from the Stone which was released on April 2017 in limited release, video on demand and digital HD.