Megan and Brandy say their 69-year-old grandmother, Gail, believes she has been in a romantic relationship with the rapper Post Malone for the past two years.

“She is convinced that they’re engaged,” says Brandy.

Megan says, “It’s like having a teenaged grandma – running around, sneaking with some guy.”

The women say they believe their grandmother is being scammed by someone posing as the multi-millionaire musician, and they’re concerned for her safety, her bank account, and her reputation.

Tune in to Monday’s episode of Dr. Phil, “‘Post Malone’ Love Story or Scam?” to find out why Gail insists her relationship with the musician is real.

Check your local listing to find out where to watch.

WATCH: ‘My Girls Think I’m Mental And Crazy – And I’m Not,’ Says Grandmother

TELL DR. PHIL YOUR STORY: Want Dr. Phil to investigate a situation or possible scam?