In a shocking episode on Thursday (29.09.16), the troubled Holly - who has battled drug addiction - passed away following an overdose and her lifeless body was found by her devastated mother Moira and brother Adam.
She returned in March this year and although fans knew she had quit the show, there had been no inkling her character would be killed off.
Powles explained: "I always knew I was only coming back for a six month storyline and I knew it was going to be drug related and heart breaking".
She said: "I think it would have been weird, you know, 'What's she doing in my house?' We just wanted to keep it under wraps".
"This is Holly's personal story".
Viewers were stunned when Holly Barton died in last night's episode without any prior warning as she took an overdose.
It was impeccable and award-worthy acting, don't you think?
Jai had always been battling a drug addition of his own, and some are speculating that he could have been the one who supplied his girlfriend with her fatal overdose.
Unable to help her son in his grief, Moira turned against Adam and it was left to girlfriend Victoria Sugden to comfort him.
Sophie said: "Holly and Moira have an incredible relationship and have really bonded recently and I'm proud of the relationship we've created".
A third said: "adam and moira gonna have to cope with holly AND james dying??? this is unfair even on a soap level wtf".
She added: "I have been so touched and inspired by all the people I have had the pleasure to meet and learn from. I was fine until the last day and then suddenly it all felt so real". "She has an addictive personality and it spiralled out of control - and we've really seen that whole storyline play out with her recovery and relapse". "Feels like I've been keeping this no so #jolly secret for ever!"