Britney Spears' little sister has confirmed she's engaged to wed the father of her unborn baby - without saying a word.

Actress Jamie Lynn Spears wore a brown T-shirt proclaiming, `The Rumors Are True' during a very public shopping trip in Baton Rouge, Louisiana on Thursday.

The 16 year old is said to have shown off her new engagement ring to friends earlier in the week after boyfriend Casey Aldridge proposed to her.

The pregnant teen and a friend were spotted in Baton Rouge at a Babies `r' Us store, where they reportedly spent almost two hours gathering gift items for an upcoming baby shower.

Shoppers who caught sight of the TV star claim it was clear Spears is expecting a son, because the items she was selecting were mostly blue - the traditional colour for baby boys.