Britney Spears has apparently said she’s “disappointed” in her sister for falling pregnant aged 16.

Britney, 26 – who has two kids with her second ex-husband Kevin Federline – has told friends she can’t believe Jamie Lynn has failed to follow her advice and sacrificed her adolescence at such a young age.

The People quotes her as saying, “I'm really disappointed in her. I told her over and over just to be a kid and let the adult things like sex and drinking and all that wait.

"I just can't believe she's pregnant. She is way too young to be a mum. She should be having fun and stuff, not having a baby."