Sheridan Smith has confessed Cilla Black gave her her number but she was too scared to call her.
The Bafta-winning actress plays the legendary singer and TV presenter in a three-part biopic for ITV about her life.
Sheridan revealed Cilla was fully supportive of her portrayal.
"She gave me her number actually, and said I could call her. I was too shy," she laughed. "You can't ring Cilla Black every day! I left her in peace and got on with filming."
Cilla has since described Sheridan's performance as "absolutely terrific... God knows how she sang so well with those false teeth in".
But the actress admitted she was conscious of not doing an impersonation of the star.
She said: "A lot of people mimic Cilla, don't they? I didn't want to do her a disservice. There are hints and mannerisms in there, but it's our version of her."
:: Cilla begins on ITV on Monday, September 15.