The ultimate role for Lyn Paul as she returns to the part of Mrs Johnstone in Blood Brothers at the Wycombe Swan

This was a role she first played in 1997, revised in 2008 and last played in the final West End performances of the play, written by Willy Russell, in 2012.

She admits it is her ultimate role. “Mrs J is just me. Everything she is going through I feel, the way Willy’s written it, makes it so easy to get over to an audience, as it’s actually written as you would speak.”

Hailed as one of the best musicals of all time, Blood Brothers tells the captivating and moving story of twin boys separated at birth, only to be reunited by a twist of fate and a mother’s haunting secret.

The memorable score includes A bright New Day, Marilyn Monroe and the emotionally charged hit Tell Me It’s Not True.

When Mrs Johnstone is deserted by her husband and left to her own devices to provide for seven hungry children she takes a job as a housekeeper in order to make ends meet. In a moment of weakness and desperation she enters a secret pact with her employer which leads inexorably to the show’s shattering climax.

Ms Paul says the story touches many lives. She said: “I got a letter once from a woman who had a son who was in jail, and she said she sat watching it and it was the only time she’d ever seen anybody portray on stage a jail sequence as it is. And she said she cried and cried. So if that’s one example, you can image how other people must relate to other parts of it. Everyone’s going through highs and lows and a lot of what Mrs J’s goes through. And Mrs Lyons. And Mickey and Eddie.”

Ms Paul rose to fame in the early 1970s as a member of the New Seekers, coming second in the 1972 Eurovision Song Contest with Beg, Steal or Borrow. The band also had a best selling hit with I’d Like To Teach The World To Sing, adapted from an advertising jingle, which went on to sell over 20 million copies and still remains one of the 100 best selling singles in the UK.

She said: “We recorded the advert first for Coca Cola and then everybody said, ‘wow, what a fantastic song,’ although the five of us looked at each other and said, ‘what?’

“But everybody turned out to be right and we went into the studio and recorded the single and the rest is history. And it crops up all the time. It was in the last ever episode of Mad Men, it was a perfect way to end that show and a very proud moment for us.”

Blood Brothers is at Wycombe Swan at 7.30pm from Monday (April 11) through to Saturday 16 with an additional 2.30pm matinee on the Saturday. Tickets cost from £17 to £35 and are available from the box office on 01494 512000 or online at www.wycombeswan.co.uk