Britney's sister pregnant

Britney's 16-year-old sister - expecting first baby

Jamie Lynn Spears - Britney's 16-year-old sister - has announced she's expecting a baby.

Rather than share the news with her family first, Jamie Lynn chose to broadcast her good news via American OK! magazine, which is where Britney first learnt about it.

'It was a shock for both of us, so unexpected,' the young TV presenter told the magazine. Adding of 19-year-old boyfriend Casey Aldridge, 'I was in complete and total shock and so was he.'

Big sister Britney has since released a statement to E! News, saying she 'wishes her sister nothing but the best and asks for privacy during this time'.

Mother Lynne tells OK!: 'I didn't believe it because Jamie Lynn's always been so conscientious. She's never late for her curfew. I was in shock. I mean, this is my 16-year-old baby.'

In other Spears-related drama, tabloids in the States are today reporting that Britney is planning a third marriage, to Sam Lufti.

'Britney is completely under Sam's spell,' a source tells Star magazine.

If she does go ahead with the wedding, ex-husband Kevin Federline claims he'll press on with plans to ban her from seeing her children completely.