The former S Club 7 singer welcomed the new arrival on Tuesday. The couple are yet to announce the name they have chosen for their baby daughter, who weighed in at 7lbs 7oz.
Rachel's husband Alex Bourne shared the happy news on Twitter. He wrote: "Delighted to announce the safe arrival of our gorgeous little girl! @MsRachelStevens and baby both really well.
"Amelie happy and ‘cited (sic)" the tweeted continued, in reference to the pair's three-year-old daughter Amelie.
Delighted to announce the safe arrival of our gorgeous little girl! @MsRachelStevens and baby both really well. Amelie happy and 'cited' x— Alex Bourne (@bourneskilove) April 1, 2014
In a statement released later by the second-time parents they revealed that they were 'totally smitten' with their newborn within minutes of her birth.
They said: "We're so happy that baby has arrived safely. Within minutes of meeting her we were totally smitten. "
And they're not the only ones – Amelie is over the moon at the prospect of having a little playmate. "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," they said.
Last month the brunette singer posted a snap of her blooming baby bump on Twitter.
"BABY BUMP - I'm starting to nest as it's not long to go now! she wrote alongside the picture," she wrote.
Rachel, 35, shared her pregnancy news on her website, alongside a sweet picture 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.
Rachel and Alex have been married four and a half years. They tied the knot in 2009 in a lavish afternoon ceremony at Claridge's hotel in London's Mayfair.