Bobby Brown first realised his former wife Whitney Houston had a drug problem when he watched her snort cocaine on their honeymoon, but insists he could not help the tragic singer.

The My Prerogative hitmaker sat down for a candid Tv chat with U.S. newswoman Shaun Robinson for a special, titled Bobby Brown: Remembering Whitney, which aired on Saturday night (17Jan15), and he opened up about his 15-year marriage to the R&B diva, who lost her life in 2012.

Asked about first realising his wife was hooked on cocaine, Brown, who has also battled substance abuse issues, revealed he first saw her taking drugs on their honeymoon, but felt powerless to stop his new wife.

He told Robinson, "I was her husband and I guess some people would think that I could have done something... I did as much as I could do.

"She was my heart... That was my girl and if there was anything more I could have done, I swear I would have done it."

Brown also revealed all about the end of the marriage, confessing he didn't realise his wife was serious about a divorce until she served him with papers in a Chinese restaurant.

He added, "When the papers came to me, I was at a Chinese restaurant and somebody called me on my phone and was like, 'We have this cheque from such and such', and delivered it... 'You've been served'."

The Brown expose premiered on Tv in America before the debut of actress Angela Bassett's new Houston biopic, Whitney.