Brown made the announcement through a Twitter post on Thursday.
“@nickdgordon #HappilyMarried SO#Inlove if you didn’t get it the first time that is,” she tweeted along with a photo of her hand placed over Gordon’s, both wearing what appear to be wedding rings.
Nick Gordon was raised by Whitney Houston like her own son and the two have lived under the same roof for years.
Gordon reportedly was taken in by Houston more than a decade ago and had lived with the family in her Atlanta home for years.
Bobbi Kristina, 20, announced that she was engaged to Gordon, 24, in October 2012.
They broke up shortly afterwards, but then reconciled and renewed their engagement in July 2013.
“YES, we me nick are engaged. I’m tired of hearing people say ‘eww your engaged to your brother or if Whitney was still alive would we be together or would she approve of this,'” she wrote at that time on her Facebook account.
“Let me clear up something, we aren’t even real brother and sister nor is he my adoptive brother. My mom never adopted him. In fact, mommy was the one who even said that she knew that we were going to start dating. My mom knows me better than any of you,” Brown added.