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"Baby Harper is the most beautiful baby girl I have ever seen, I have fallen in love all over again!!!" Beckham wrote on her official Twitter page.
She added that her three boys with soccer superstar David Beckham -- Brooklyn, Romeo and Cruz -- are enjoying their new sister too. "We all feel so blessed and the boys love their baby sister so much!!!"
Harper Seven was born Sunday morning at Cedars-Sinai Medical Center in Los Angeles, weighing 7 lbs., 10 oz.