The former S Club 7 singer, 35, and her husband Alex Bourne, who also have three-year-old daughter Amelie, welcomed their second child into the world on Tuesday (01.04.14).
Alex proudly announced the news on Twitter, writing: "Delighted to announce the safe arrival of our gorgeous little girl! @MsRachelStevens and baby both really well. Amelie happy and 'cited (sic)"
The couple, who have yet to reveal their newborn baby girl's name, also released a statement saying: "We're so happy that baby has arrived safely. Within minutes of meeting her we were totally smitten. Amelie is happy and 'cited to have a little sister to play with and we can't wait to introduce her to the whole family."
Rachel first confirmed she was pregnant again in September, tweeting: "Alex and I are so happy to find out that we are pregnant again and can't wait to meet our new little member of the family early next year.
"Needless to say, we're all super excited, especially Amelie who is looking forward to meeting her new little brother or sister."
The brunette beauty, who married Alex in 2009, previously revealed they had found out the sex of their baby but kept it a secret until her arrival.