Appearing on Good Morning Britain, the Rocky actor explained his friend Arnold Schwarzenegger put him onto the doco.
"I checked it out and figured I'd try it," he told hosts Piers Morgan and Susanna Reid.
The flick claims that going vegan can help boost your erections, so naturally the pair asked Lundgreen whether he'd notice any difference to his bedroom game.
"Well, it was already quite good. It went up about 50 percent.
"I think maybe a little bit," he continued. "I'm a lover, not a fighter."
Jokes aside, Lundgren did confirm he has a lot more energy these days.
While Hollywood A-listers have been quick to jump on the new fad, claiming they've seen numerous benefits after turning to the diet, it's important to realise that you can miss a lot of crucial nutrients that are rich in animal-based products.
“Ultimately, it's not that getting people to eat plants is a bad thing. It's generally a great thing. But you don't have to do so by erroneously telling people that meat is killing them, and they need to go to an all-plant diet. That is a false dichotomy,” Brian St. Pierre., M.S., R.D., C.S.C.S., Director of Performance Nutrition at Precision Nutrition, previously told Men's Health.
If you are turning to a plant-based diet, here's a how you can find the necessary amount of protein.