The actress, who plays Deirdre Barlow in the soap, appeared at Preston Crown Court on Wednesday as a character witness for her on-screen husband Roache, who is accused of a number of sex offences.
The actor denies the charges of two counts of rape and four counts of indecent assault involving five complainants aged 16 and under between 1965 and 1971.
Giving evidence from the witness box, Ms Kirkbride was asked what one word she would use to describe Roache.
She replied: "Lovely."
Ms Kirkbride 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.
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.
"We shared a lot of the same interests in spiritual things. I just found him very easy to talk to."
When asked, the actress told the court there was "never" anything worrying about Roache's behaviour towards young women, including the younger members of the Coronation Street cast.
She said: "He has obviously been in the company of younger cast members on a work basis.
"We have had several young actresses play the part of our daughter.
"He has never been anything other than helpful and supportive.
"There was never a hint or suggestion of anything else in all the years that I have known him."
Fellow cast member Chris Gascoyne, who plays Peter Barlow, was next to be called to the witness box.
Asked to describe Roache's character based on his time working with the actor, Mr Gacoyne replied: "Kind, warm, open, good sense of humour. Professional."
He told the court there was "nothing untoward" about Roache's interactions with young women while in the studio, describing it as "completely normal".
Under cross-examination from Anne Whyte, prosecuting, Mr Gascoyne agreed that by the time he joined the show he was 32 and Roache was 72.
Actress Helen Worth, who plays Gail McIntyre, was next to give evidence, telling the court Roache was "very caring" and "welcoming" to her when she joined the cast of Coronation Street in 1974.
"And he has been to every new member of the cast since," she added.
Asked how she would describe his character, especially to young women, Ms Worth replied: "He was caring. Never anything more. Just caring. What more can a man be? He was lovely."
Louise Blackwell, defending, then asked her: "Did you see him in the company of young female cast members?"
"Yes, of course," she said. "I never saw anything that was untoward whatsoever in 40 years."
Earlier ITV employee John Friend Newman told the jury he had worked as a floor manager on Coronation Street since 1979.
He said his role has been to control the studio, the filming, access and "all aspects of discipline within the studio realms".
Members of the public were not allowed without permission inside the building in Quay Street, Manchester.
All visitors, including family members of the soap's cast, would have to ask floor managers if they could enter studio areas.
People would be challenged on the corridors if not recognised, he added.
One of the alleged victims claims Roache groped her in a dressing room, while two others say he sexually assaulted them in studio toilets.
The trial continues.