Priscilla Presley’s alleged friendship with Bam Margera appears short-lived, she’s ripping the “Jackass” star for claiming she gave him one of Elvis’ rings and robes … telling us Bam made the whole thing up.

Priscilla tells TMZ … Bam has betrayed not only her, but also her son Navarone Garcia, by falsely claiming she gifted him a couple of Elvis’ personal items and filming in their home without her consent.

It’s a stark rebuttal to what Bam told us earlier this month … when he claimed Priscilla gave him a robe and a ring that once belonged to Elvis. Bam said he was going to pass the robe along to his dad, who is a big Elvis fan, and give the ring to Yelawolf, who Bam considers the new king of Rock ‘n’ Roll.

Remember … the friendship seemingly popped up out of nowhere last week, when Bam posted pictures and videos of him hanging out with Priscilla.

Bam made it seem like he and Priscilla were buddies, but she says that statement couldn’t be further from the truth. Instead, Priscilla tells us Navarone asked her to have a “new friend” come over for a visit, but she had no idea it was Bam “or that later he would choose to post photos and false stories.”

Priscilla says Bam, “came over, talked non-stop about his new ventures and personal struggles and asked for a photo with me for his father, who is a big fan.”

She continues … “Unbeknownst to us at the time, Bam chose to circulate those photos accompanied by false information and storytelling. After what Bam has chosen to do, my son and I want no further communication with him. I consider him a dishonest and unstable individual. I had no idea who he was or that he was filming in my home without my consent.”

What’s more, Priscilla’s camp says the robe did not belong to Elvis and the ring is actually one of Bam’s.

Priscilla adds … “At no time during the visit did I give him anything of Elvis’. I still have everything he ever touched. I would never disrespect Elvis who was the love of my life by giving away anything that belonged to him. I have always protected them for the fans. Elvis belonged to all of you and I cherish my life with him too much to ever squander anything.”

As you know, Bam’s been accused of falling off the wagon in his sobriety battle … and Priscilla tells us she hopes Bam “gets the help he needs and does what is right.”