Anne Kirkbride, who plays Deidre Barlow, entered the witness box at the sex abuse trial of her fellow Coronation Street veteran to testify to his good character.
She was followed at Preston Crown Court by co-stars Helen Worth, who plays Gail McIntyre, and Chris Gascoyne, who is Roache's on-screen son, Peter.
Roache, 81, was the caring and kind "father figure" and "elder statesman" of the show, who looked after younger members of the cast, the jury were told.
Kirkbride, 59, said she had never seen anything worrying about Roache's behaviour on set with young women from when she joined the show in about 1972.
Louise Blackwell, QC, defending, asked the witness how she felt on joining Coronation Street.
She replied: "I was terrified for my first day. Very nervous going. It was a completely new situation. I didn't know anybody. I very quickly got to know people and it became easier."
Asked what she thought of Roache on meeting him, she said: "He was friendly. I remember the first time I spoke to him was outside a lift and we had a really nice chat and he offered me a cigarette."
Helen Worth, 63, told the jury she joined the show in 1974, aged 23.
She said she was "extremely nervous" when joining the show "as any young actor is to this day" but she was soon made to feel welcome.
"But Bill perhaps was caring more and welcoming to me then," she added, "And has been to every new member of the cast since."
Mr Gascoyne described him to the jury as: "Kind, warm, open, good sense of humour. Professional."