In a clip from this week's episode of Joan & Melissa: Joan Knows Best, Joan Rivers is seen hot-boxing a parked car with a friend. The 78-year-old comedienne has a prescription for medical marijuana—she received it for pain management purposes after getting a face lift. Joan and her friend Lynne smoke a bowl of pot from a pipe they've named “Louis the Thirteenth.” They get so high that Rivers needs to call her daughter Melissa to come get them. The clip also shows Rivers having crazed food cravings, talking nonsense and jumping in a spa, happily fully clothed. Rivers tells The Huffington Post that she hadn’t gotten high since the “dark ages,” when she used to smoke pot with Betty White. “Well, I had a very difficult moment there after the surgery and I got medicinal drugs,” she says. “In California you get medicinal marijuana. You go to a doctor and you say I'm blue and he says, here. It's amazing. I was in shock. And I got it and I smoked it and had a great time."