Tito Ortiz -- Before Jenna Jameson Bashes Me on TV, Know This ... She's A LIAR

Tito Ortiz is scrambling to protect his reputation in the face of a public smear campaign ... helmed by his baby mama Jenna Jameson -- telling TMZ, whatever she's about to say on TV is bound to be filled with lies ... because she's a dirty liar.

FYI, Jenna recently sat for an interview with "Entertainment Tonight." It's unclear what the interview is about, but Tito's guessing he's a main talking point ... and given their sordid history, he probably isn't portrayed in the best light.

So he's coming out to clear his name preemptively -- telling us, "I want to make it very clear that any and all allegations she has made about our personal life and my character are completely false. Jenna continues to paint a picture of distorted reality, which has been hurtful to both myself and my family. I hold sole custody over our boys, which speaks for itself."

He adds, "I am moving on with our life and with our boys, and I pray this is all over soon. I wish Jenna would get help to not only save herself, but for the children she brought into this world."