"We can confirm that Guy and Jacqui are the proud parents of a new baby girl. Mother and baby are doing well," the director's representative told the Daily Mail newspaper in London Thursday.
No other details regarding the child's birth were immediately available.
The couple, who began dating in spring 2010, also have a 14-month-old son, Rafael, People.com said.
Ritchie has two other sons -- Rocco, 12, and David, 7 -- with his ex-wife, pop star Madonna.