I Will Always Love You, Whitney Houston sang in her mega 1992 hit.

Could that person be her best friend and assistant Robyn Crawford, given that rumours have swirled for years that they were lovers?

Based on revelations in the documentary Whitney: Can I Be Me, which premiered on Wednesday at the Tribeca Film Festival in New York, such talk could well be true.

"I don't think she was gay, I think she was bisexual," Houston's long-time friend and stylist Ellin Lavar said in the film.

"Robyn provided a safe place for her… in that Whitney found safety and solace."

According to a story in People, the film suggests that Houston, who died at age 48 in 2012, was caught in a fiery relationship between her husband Bobby Brown - they were married from 1992 to 2007 - and Ms Crawford.

"Robyn and Whitney were like twins," said Mr Kevin Ammons, a member of Houston's security team.

"They were inseparable. They had a bond and Bobby Brown could never remove Robyn."

When Houston's 1999 My Love Is Your Love world tour ended, Ms Crawford left and the singer's "downfall" started, noted Ms Lavar.

Houston was found submerged in a bathtub in the Beverly Hilton Hotel on Feb 11, 2012.

In an obituary for Esquire magazine, Ms Crawford, who is in her 50s, paid tribute to the superstar as a loyal friend.

"I loved her laughter and that's what I'll miss most," she penned.

At the premiere, the film's codirector Rudi Dolezal said: "I think that Robyn was probably the only person, at least that I met, who completely understood Whitney."

Happiness was hard to come by for the singer, according to the Daily Beast, which quoted Kirk Whalum, saxophonist on her 1999 tour, as saying: "Her favourite saying was 'Can I be me?'

"That 'I've made all this money and all these people happy and I still can't be me.'"