The couple, who announced the pregnancy in August are already parents to sons James and Wellington, and daughter Vivienne, reported People Magazine.
Daughter Bridget Monroe Pope was born weighing 7 pounds on Thursday.
"Bridget and Rosie are doing great!" her rep has told.
"We feel so blessed and the rest of our brood are so excited to have another baby in the house," fashion designer Pope had said after announcing she was pregnant.