Geri Halliwell has insisted the Spice Girls musical Viva Forever! is "good entertainment" - and admitted she had been "cocky" about it being a success.
The show, featuring songs from the hugely successful girl group and created by Jennifer Saunders and producer Judy Craymer, is closing in February next year.
The former Ginger Spice, who is heading Down Under to be a judge on Australia's Got Talent, mused on her website: "God only knows why things don't work. It's 11pm and I've just come back from the West End theatre show Viva Forever! - To say goodbye.
"Over four years ago it started with a conversation in a kitchen; Laughing...joking...full of promise, dreams and optimism. We managed to get one of the most successful theatre producers to do our show! A great writer, our Spice music... I felt confident - almost cocky it was going to be a huge success."
The 40-year-old singer admitted: "It didn't work - six months later, it's closing. What went wrong? Was I biased? Blinded because it was a show with our music?
"Was it the lighting? The set? The choreography? The press? The story? It had a bumpy start but the cast and director worked really hard, made great changes, and I can hand on heart tell it's not s**t! - It's good entertainment! I've learnt in life that sometimes things just don't work out, at least not how we hoped."
Geri - who said she will try to "have a blast" in Australia in her search for a star - thanked the brains behind the musical, as well as cast, crew and fans.
"It's hard to say goodbye, but sometimes we just have to..." she wrote.