The ‘Eastenders’ actress, 33, known as Sonia Fowler in the soap, shared a family photo on Twitter with her newborn daughter.
@cameramarc and I introduce Joanie Elizabeth Cassidy-Humphreys,” she wrote on Monday 29 August 2016. “We are all so in love!”
The family photo featured her fiancé Marc Humphreys and her five-year-old daughter Eliza from a previous relationship.
Cassidy was congratulated by fans and colleagues on Twitter, including many ‘Eastenders’ fan accounts.
“Evening all... time to let everybody know that @cameramarc and I are having a baby in the summer,” she tweeted.
“The three musketeers become four.”
The actress announced her engagement to Humphreys in October 2015.