The 61-year-old actress, who plays Gail McIntyre in the ITV1 soap, is engaged to 54-year-old deputy headteacher Trevor Dawson following his proposal last month.
The couple, who have been dating for over a year, plan to marry in front of family and close friends before the end of summer.
"Everyone in the cast is thrilled for Helen - nobody deserves to find happiness more than her. If everything goes right they could be man and wife by the end of the year - they don't see any point in dithering," a friend told The People.
"The one thing missing from her life for many years was a loving partner to share in her success. She has found that in Trevor and everybody is overjoyed for the pair of them.
"It's a long-distance love affair that has gone the extra mile and they're so good for each other. Helen has always been a very private person, but it's plain to see how delighted she is with the development in her love life.
"These days she appears to be smiling all the time - the fans would hardly recognise her after having to portray all that awful anguish for so many years. Her engagement is brilliant news - she's been besieged by genuine friends wishing her every happiness."
Worth divorced actor Michael Angelis in 2001 after 21 years together when he confessed to having an affair.
A Coronation Street spokesman last night confirmed the engagement.