Whitney Houston's daughter has stunned family by admitting she's set to marry her adopted brother.

Bobbi Kristina Brown is engaged to the young man her mother cared for like a son, Nick Gordon.

The revelations were broadcast in a new trailer for the reality TV show, The Houstons: On Our Own.

Kristina, aged 19, is seen telling her family she is engaged to marry 22-year-old Gordon.

Whitney informally adopted Gordon when he was 12-years-old, raising he and Bobbi Kristina as siblings.

A spokesperson for the show said viewers would have to wait and see the full story come out.

The show premieres on Lifetime Wednesday, October 24.