Bobbi Kristina’s uncle Gary Houston expressed deep concerns over his niece’s alleged drug use.

The 19-year-old is the daughter of late singer Whitney Houston and New Edition crooner Bobby Brown.

Bobbi Kristina’s parents both struggled with addiction to narcotics and the teenager is also rumoured to have inherited the disease.

On the latest episode of the family’s Lifetime reality TV show The Houstons: On Our Own, Gary revealed his thoughts on Bobbi Kristina’s welfare.

"Her behaviour, it's just not normal," Gary said to Whitney’s former bodyguard Ray Watson.

Apparently Gary believed that the family should keep a close watch on Bobbi Kristina.

He asked that Ray pay special attention to her.

"We got a situation that we need to address when it comes to [Bobbi Kristina]," Gary declared.

"I don't know what's happening, but something's going on."

Bobbi Kristina is engaged to Nick Gordon, who Whitney treated as her adopted son.

Bobbi confirmed the news in a promo released for the reality show The Houstons: On Our Own, where her aunt Pat Houston termed the romance “unacceptable”. Other family members are reportedly also struggling to accept the union.