The former EastEnders star and husband Tom Ellis have named their daughter Florence Elsie Ellis.
A spokesperson for the couple said: "We are pleased to announce that Tamzin Outhwaite and Tom Ellis are the proud parents of Florence Elsie Ellis who arrived last week."
Outhwaite, who played Melanie Owen in the BBC soap, wed Ellis in 2006.
She has previously hinted that she would be willing to give up her acting career to focus on starting a family.
"My career and ambitions have been fulfilled, and I would be quite happy not to work again and look after the children," said Outhwaite.