The former Hear'Say singer, who has 3-year-old daughter Ava with husband Graham Quinn, made the announcement this afternoon via micro-blogging site Twitter.
She said: "Woo hoo! I'm pregnant! So happy!!
Later, she thanked her followers for sending congratulations messages, adding: "Crikey, still reading all your msgs. Bumps gona have a lot of aunts and uncles!
The 32-year-old recently revealed that she had volunteered at a London maternity ward, saying that midwifery is "more worthwhile than almost anything else".
