Bobbi Kristina Brown has got engaged to her 'adopted' brother Nick Gordon.

Related: Bobbi Kristina makes her acting debut

The aspiring actress - the daughter of Bobby Brown and the late Whitney Houston - surprises her dismayed family with the news in a preview from her upcoming reality show 'Houstons: On Our Own', nervously telling them: "We're engaged!"

Nick was informally adopted by Whitney when he was 12 and the pair were raised as brother and sister. They were "always close" growing up but their relationship changed as they got older and they sought comfort in each other after Whitney's death in February and started living like a couple in Atlanta.

The reality series will follow the pair and other family members - Whitney's brother Gary, sister-in-law (and the singer's former manager) Patricia Houston and Bobbi's grandmother Cissy Houston - have coped with life since the tragic passing of the 'I Will Always Love You'.

Cissy recently announced her concern for her 19-year-old granddaughter Bobbi if she inherits the multi-million dollar inheritance left to her by her mother.

Cissy fears the teenager will be corrupted by the "negative influences" in her life if she gets the cash, but it would seem that Bobbi Kristina is out to cause drama within her family.

Bobbi Kristina adds in the promo for 'Houstons: On Our Own': "They wanna see us fail. I've got one thing to say, 'You won't!' "