Al Bowman claims that the late singer was by far the worst behaved star he had in the back of his limo.
He claims to have driven the singer to run down ghettos to pick up crack from dealers, witnessing Bobby and Whitney having a threesome with an A-list soul singer and that she'd smoked crack in front of her daughter.
Irresponsible: It's claimed that Whitney Houston smoked crack in front her daughter Bobbi Kristina when she was just six years old
Al told the Daily Mirror: 'I couldn’t believe my eyes, here was Whitney Houston in the back of my limo smoking crack with her six or seven-year-old daughter sat next to her playing with a doll, it was heart-breaking, out of control.
'I’ve driven some big stars over the years – Michael and Janet Jackson, Ozzy Osbourne, Motley Crue – but Whitney was by far the worst behaved.
'It was tragic to see. Here was this glamorous superstar adored around the world, but in the back of my car she was a rambling drug addict, a complete train wreck.
'It was so sad, I wanted to help her but she was just too out of control and wouldn’t listen to anyone.'
"Adult things": Bobby Brown and Whitney with their daughter in 2004
He later added: 'Their daughter Bobbi got into the limo with them. Then they would smoke crack right in front of her.
'Whitney would just say, "Baby, Mommy and Daddy are doing adult things", it wasn’t anything major to her.'
Meanwhile it has been claimed that Whitney binged on cocaine, alcohol and pills in her final months.
Insiders says that after months of sober living during 2011, the tragic star fell off the wagon.
In mourning: Bobbi Kristina arrives for the private wake of her late mother in Newark, New Jersey
A source told Star magazine: 'The last three months of Whitney's life were truly tragic.'
Whitney was found dead in the bathtub of her Beverly Hilton hotel in Los Angeles on the eve of the Grammy Awards.
Eyewitness told the publication about Houston partying at Hollywood club Playhouse on January 2.
'Whitney got buck-wild. She drank cognac and champagne and seemed completely out of it from the moment she arrived until the moment she left at 2.30am.'
Troubled: Whitney, seen with her daughter Bobbi was said to have binged on drugs and alcohol ahead of her death
The reports goes on to detail her partying at the luxury Beverly Hills hotel, the Beverly Wilshire.
'Whitney was in a lounge chair drinking pina coladas all afternoon,' another eyewitness told the magazine.
'Once in a while, she would get on her cell phone and start screaming at someone. She seemed almost manic at moments and practically unconscious the next.'
Her wild behaviour continued right until her death.
It has been claimed that those close to Whitney, including her daughter Bobbi Kristina wanted her to seek treatment in rehab in the weeks leading up to her death, it has been reported.
An insider told RadarOnline.com: 'Bobbi Kristina, Clive Davis, and members of Whitney’s closest advisers were urging her to go back to rehab because people close to her saw her downward spiral into drugs and alcohol.
'It was extremely hard for Clive in particular to see Whitney under the influence again. He was absolutely powerless to stop her. Clive and Whitney had a very close relationship, but her addiction to drugs and alcohol did a lot of damage to that.'
The website also claims that Davis was willing to pay for the treatment but Whitney is said to have refused the help.
CNN anchor Don Lemon claimed he saw Houston doing somersaults in the pool just days before she died - saying she had been drinking alcohol from as early as 10am.
Sombre mood: Ray J, who has finally spoken out about Whitney, was seen at LAX earlier today catching a flight to New Jersey ahead of the late singer's funeral tomorrow
Statement: Ray J said: 'Over the past few days, I've tried to process the emptiness that I am experiencing. What my heart feels cannot be expressed in words. The world lost an icon, but I lost my close friend'
Houston will be laid to rest tomorrow after a funeral service at New Hope Baptist Church in her hometown of Newark, New Jersey.
Meanwhile Ray J, who was dating Whitney in the months before her death has finally broken his silence.
The 31-year-old released a statement that said: 'Over the past few days, I've tried to process the emptiness that I am experiencing. What my heart feels cannot be expressed in words. The world lost an icon, but I lost my close friend.'
Alluding to a nickname given to Whitney by her father he added: 'Nippy, I miss you so much!'
'You were so happy and full of love. Your smile will live in my heart forever.'
Paying tribute: Fans around the wold are preparing for the funeral tomorrow. A fans signs a tribute wall in Philippines
Ray J was seen at LAX airport today catching a flight to New Jersey ahead of Whitey's service tomorrow.
There will be a galaxy of stars paying tribute to the singer including Kevin Costner, Arethan Franklin and Stevie Wonder - the final duo who will be performing.
Today it has been revealed that Mel Gibson reached out to the I Didn’t Know My Own Strength singer a few years ago to try and deal with her addiction issues.