The former Girls Aloud singer took to Twitter on Monday evening to announce the news.She said: "I am overjoyed to let you know our little girl is here. She is amazing! I love being a mammy & will fill you all in soon. Love Nadine Xx."Nadine, who is 28, revealed last year she was expecting her first child with American football player Jason Bell.Her bandmate Cheryl Cole was first to congratulate her, tweeting: "It is OFFICIAL!! There is a baby Aloud!!!!!! Congratulations @nadinecoylenow & Jason so amazing!!!"