JAMIE-LYNN SPEARS rendered her mother LYNNE speechless when she revealed she was pregnant at just 16.

On Tuesday (18Dec07), Jamie-Lynn admitted she is 12-weeks pregnant with her first child with boyfriend of two-and-a-half years, Casey Aldridge, 18.

The TV star sister of Britney Spears was so scared, she broke the news in a note - and Lynne refused to believe her at first.

Jamie-Lynn says, "She didn’t really say anything at first. She just kind of looked at me. It was me and Casey that told her. She didn’t believe us. But then she looked at Casey and he’s always been very straightforward, and then she knew it was real. She was very upset because it wasn’t what she expected at all."