Melanie Chisholm – Sporty Spice – was speaking as signed copies of her sixth solo album at the HMV store in Glasgow Buchanan Street.
Stages is a collection of showtune covers, inspired by her time spent watching productions in the West End and later starring in two.
Mel appeared in Blood Brothers in 2009 and is currently playing Mary Magdalene in a touring production of Andrew Lloyd Webber's Jesus Christ Superstar.
While working on the album, she was reunited with Emma "Baby Spice" Bunton, who features on the track I Know Him So Well, from Chess.
"It was so lovely to work with Emma again," said Mel.
"Hearing our voices together is really emotional and I'm really happy with how the song sounds."
At the signing, at HMV, Mel had a surprise visit from her Jesus Christ Superstar co-star, ex Radio 1 DJ Chris Moyles.
The pair will be on stage at the SECC tonight, with Moyles starring as King Herod.
Mel said: "I was waiting to see a familiar face out there in the crowd.
"I wondered if someone would pop up and Chris was here and some other guys from the cast. It was nice to see a friendly face."
Mel said it was "absolutely brilliant" to meet her supporters.
Carrie Griffiths, 31, from East Kilbride, said: "I'm completely speechless. I've been a fan for a long time and she was lovely."