The 8-year-old daughter of singer Jamie Lynn Spears is in serious condition following an ATV crash, according to TMZ and other online media outlets.

The celebrity news website only cites "sources" close to the Spears family but says the girl, named Maddie, was on an ATV that overturned and she may have been under water for a few minutes. She was on a hunting expedition.

Her mother was not with her at the time of the crash, TMZ reports.

Jamie Lynn is the younger sister to pop superstar Britney Spears. She was first on the entertainment scene when she appeared in the movie "Crossroads," playing a younger version of her sister.