The 35-year-old former Spice Girl made the revelation last night on her Heart 106.2 London radio show, reports the Daily Mail.
The 'Dancing On Ice' star had earlier teased that she had 'big news' as she started her broadcast.
The star, who announced her engagement to long-term partner Jade Jones live on Dancing On Ice last month, already has little boy, Beau Lee Jones.
Jones was born on 10 August 2007.
The singer has been with the former Damage boyband-star-turned-chef for 11 years and announced in November that they were expecting their second child next spring. (ANI)