Anna Nicole Smith exchanged vows with her lover Howard K. Stern less than three weeks after her son died -- and before she buried him -- because the grief-stricken mom couldn't bear going on "alone in life," Stern said.

"For anybody to try and judge us and to try and say we're doing what's right or what's wrong, there's no way for anybody to understand what Anna was going through when Daniel passed," Stern, who has also been Smith's lawyer, said in an interview the couple gave "Entertainment Tonight" and "The Insider" that airs Thursday and Friday night.

"For Anna and for myself, we felt like we needed it and Anna needed it; she didn't want to be alone in life," her longtime friend said.

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Smith and Stern participated in a nonmarriage "commitment ceremony" 18 days after her son, Daniel, 20, died on Sept. 10 in her hospital room in the Bahamas, where she had given birth to a daughter three days earlier.

The two have been secretly involved for years -- and it was she who made the first move, Smith said.

"I wanted more than a lawyer relationship, and then started kind of flirting with him and we kind of got it on. I just kind of attacked him and that was it. I kissed him first. He was the shy one," she told interviewer Mark Steines.

"He was like, 'I can't, I can't,' because he always had to go by the books," she said. " I knew I was in love the first time I kissed him."

Stern said they kept their love quiet because they were overly concerned about how people would perceive the relationship.

"This has been going on for years," he said. "Unfortunately, we have a lot of enemies who we thought were gonna try and hurt us in certain ways."

The former Playboy model shrugged off criticism about the timing of their commitment.

"Don't worry about us. Worry about your own self," she said.

Smith was holding newborn Dannielynn Hope Marshall Stern during part of the interview. Smith and Stern say he's the baby girl's father, but Smith's former beau Larry Birkhead claims he's the dad, and is demanding a paternity test.

In yet another twist, a lawyer for Birkhead questioned this week whether Smith may have dyed her 2-month-old daughter's hair darker to make it appear Stern is the father. A lawyer for Smith dismissed any allegations of hair-dyeing as ridiculous.

Meanwhile, the model has been hospitalized with pneumonia at the same hospital in the Bahamas where her son died.