The former S Club 7 singer already has a three-year-old daughter with her husband Alex Bourne, who had shared their happy news on the social media site last week.
"Delighted to announce the safe arrival of our gorgeous little girl! @MsRachelStevens and baby both really well.
"Amelie happy and ‘cited (sic)", his tweet continued, in reference to their daughter Amelie.
"The pitter patter of (tiny) feet all 8 of them! Bursting with love… "
Rachel has been married to Alex for over four years now. The pair were married in an extravagant ceremony at the Claridge’s Hotel in London’s Mayfair.
Rachel announced their second pregnancy in September last year with another cute picture – a snap of the family's shoes with their birth years chalked underneath. Next to Amelie's pink trainers were a pair of white baby shoes with the year 2014 written in chalk below them.
"Needless to say, we're all super excited, especially Amelie who is looking forward to meeting her younger brother or sister", Rachel tweeted at the time.