The baby bump is for real. Britney Spears told David Letterman Tuesday that she is pregnant with baby No. 2.

Pop singer Britney Spears shares a laugh with host David Letterman on the set of The Late Show with David Letterman, Tuesday, May 9, 2006 in New York. Spears announced on the show that she and husband Kevin Federline are expecting their second child. [AP/file]

"Don't worry Dave, it's not yours," the pop princess quipped.

The revelation ended weeks of speculation in entertainment magazines, which have been regularly publishing pictures of Spears' apparently expanding waistline.

Spears, 24, and her husband, backup dancer-turned-rapper Kevin Federline, 28, were married in 2004 and have an 8-month-old son, Sean Preston.

Federline also has two children, Kori and Kaleb, with his former girlfriend, Shar Jackson.

Child welfare officials and a sheriff's deputy reportedly visited Spears' home in April after her son accidentally tumbled from a high chair.

In February, authorities visited the home after photographs showed the singer in a car with her son in her lap, rather than in a car seat as required by law. Spears later apologized, saying she held the boy in her lap because of a "horrifying, frightful encounter with the paparazzi."

Spears rose to fame at 16 with a naughty schoolgirl image and the multiplatinum album "... Baby One More Time."