Oksana Grigorieva had planned to appear on Oprah Winfrey's talk show, however the Los Angeles judge handling her court case had implemented a gag order ... leaving Oksana's lawyer no choice but to cancel the appearance.

Although her interview with Lady O has been the worst kept secret, Oprah's reps continue to say, "We have nothing to announce at this time."

Grigorieva, 40, did get candid with People Magazine about the alleged abuse she suffered from her ex Mel Gibson.

The Russian-born singer tells the mag:

    "I thought he would kill me... I needed to document his threats. I'm not angry at him. For the sake of [daughter] Lucia, I really want him to be well. He has to have the courage to be responsible for what he's done."

In the interview, she also discusses how Gibson, 56, talked about killing himself and pulled out a gun in front of her.

A gag order remains in effect for both Gibson and Grigorieva.