From where we're standing, 30-year-old Katherine looks like the girl with everything. Disney-princess good looks, a phenomenally successful singing career, a reported £13million in the bank, and a tall, dark, handsome fiancé in TV presenter Gethin Jones.
She doesn't so much walk as glide, a picture of elegance, always chirpy, always shimmering. It's almost as if birdsong, buttlerflies and bunny rabbits should follow her every move.
However, what did upset her was the suggestion in March that she'd moaned that her looks made it difficult to be taken seriously as a classical artist.
"I would never ever call myself beautiful..."
