Lucy Pargeter was told she would either get on really well with Lisa Riley, or they would "absolutely hate each other".
The 42-year-old actress - who plays Chas Dingle on the ITV soap - has heaped praise on her co-star, and admitted fellow castmate Dominic Brunt (Paddy Kirk) thought their relationship on set could have gone either way.
She said: "Lisa\'s been amazing. She\'s obsessed with the show as in she\'s watching it and she knows what\'s happening. She\'s professional, she turns up and not only knows her lines, she knows everybody else\'s lines.
"She\'s brilliant on set, she\'s got loads of energy. Dominic said before she\'s started, \'You two are either get on like a house on fire or absolutely hate each other,\' and thankfully we get on really well.
"I think she\'s brilliant. She\'s hilarious and she\'s just full of energy and excitement."
Lisa - who initially starred in the ITV soap from 1995 to 2001 - has returned as Mandy Dingle, but Lucy has played down the chances of the character interfering in ex Paddy\'s relationship with Chas.
She added: "Mandy has turned up, but she and Chas are getting on OK. From the very beginning Chas says, \'You look at him the wrong way and I\'ll rip your head off and spit down your neck.\' I love that line!
"She\'s set her stall out and when Mandy goes to the ante-natal class with Paddy, Chas doesn\'t really get angry.
"Mandy\'s always going to be there in the background but I don\'t think Chas feels threatened by her at this point because they\'re starting afresh and are just about to have this baby.
"Everything that happened last year is hopefully going to be made more palatable by the arrival of this new baby and hopefully can only make them stronger."
