Britney Spear's sister Jamie Lynn Spears has healthy baby girl

amie Lynn, 17, who stars in Nickelodeon's television show 'Zoey 101', was said to be doing well after the birth of 7lb 11oz Maddie Briann.

The star, then 16, announced her pregnancy in December through an article in OK! Magazine.

The news provoked heated debate in the US about teenage sex and Miss Spears' position as a role model to young viewers.

The father is 19-year-old Casey Aldridge, a pipe-layer from Liberty in Mississippi, to whom she became engaged in March.

The Spears family, including pop singer Britney, were at the hospital in McComb, Mississippi for the birth, at 9.30am local time.

The sisters' father Jamie Spears, spoke of his delight at becoming a grandfather.

"We're thrilled, we're all absolutely thrilled", he told America's Life & Style magazine.

The younger Spears is expected to receive a substantial amount for exclusive pictures of the newborn child.

A spokesman for Nickelodeon said: "We wish her and her family well."

In the television show, Spears portrays Zoey Brooks, a student at Pacific Coast Academy, which until her arrival is an exclusive all-boys boarding school.