Hulk Hogan just called in to "TMZ Live" ... and was completely stunned when we told him about the footage of his BFF Bubba the Love Sponge plotting to profit off of his sex tape ... telling us, "I'm sick to my stomach right now."
Hogan says Bubba had adamantly denied having any knowledge about the sex tape ... and told Hulk he didn't know there was a camera capturing Hogan's X-rated session with his former wife Heather Clem.
Hulk says he had warned Bubba ... "If you had anything to do with this, that means we were never friends."
We broke the story ... Bubba appears at the very end of the sex tape, after Hogan had left the room, and told Heather, "If we ever did want to retire, all we'd have to do is use this footage."
Hulk says he is exploring all of his legal options -- and promises someone WILL PAY for recording and releasing the tape.