Bobbi Kristina, daughter of tragic singer Whitney Houston, is rumoured to be secretly engaged to new love Nick Gordon.

The pair have been snapped kissing and holding hands in public, with Bobbi Kristina sporting a huge ring on her engagement finger.

Bobbi and Nick are not blood relatives. He was taken into the Houston household by Whitney when he was just 12, after his father went to prison and his mother was unable to take care of him.

But Whitney Houston's mother and grandmother to Bobbi, Cissy Houston, has apparently slammed the relationship.

US gossip website TMZ.com quoted Cissy as saying: "What they're doing is incestuous."

There are also reports that Cissy has requested that the Whitney Houston Estate get involved and evict him from Whitney's $1.2m Atlanta townhouse, where he is believed to be living alongside Bobbi.

Several 'sources' have also spoken out, claiming to be worried about the relationship.

"Everyone is worried that Nick is looking to take advantage of Krissy," a 'friend' told Star magazine, presumably referring to the $10m Bobbi is apparently set to inherit from her late mother, Whitney.

Picture: Getty