<br /> Britney Spears has a new niece.<br />The singer on Thursday tweeted congratulations to her sister, Jamie Lynn Spears, on the birth of her second daughter, Ivey Joan Watson.<br />"I could not be more excited to welcome baby Ivey to this world," Britney Spears wrote.<br />The 27-year-old former Zoey 101 star married Jamie Watson in 2014. She also has a 9-year-old daughter with her former fiancé. <br />
