Michelle Pfeiffer talks becoming vegan

Michelle Pfeiffer says in a new interview that hearing former President Bill Clinton talk about his health journey helped her to adopt a vegan lifestyle.

The 54-year-old actress tells Dr. Sanjay Gupta on Monday's edition of "Piers Morgan Tonight" that watching his documentary, "The Last Heart Attack," gave her plenty of food for thought.

"I was finishing up working on, I think it was 'Dark Shadows,'" she says. "And I was watching CNN, and 'The Last Heart Attack' came on."

As she was watching the documentary, which explores preventative measures for heart disease, it was Clinton's story that really hit home.

Pfeiffer, who considers herself to also be a "foodie," watched Clinton and said, "OK, Bill Clinton loves food, so there must be something to it that's making him stick to it. And also, he's smart, so he's not going to do something unless he really thinks there's some science behind it."

After reading more on the topic, Pfeiffer says her mind was made up.

"I just felt like...there was science behind it," she says. "And, you know, it was sort of irrefutable. ... I couldn't not listen to it. My father died from cancer, and the older you get, there's a lot of disease around you. And you see people struggling with chronic disease. You see people dying with terminal illnesses. And if in any way .... this is true, then you kind of have to listen to it."

Pfeiffer says she's enjoying the vegan diet, seeing that she's someone who loves carbs, and she has her husband of 19 years, David E. Kelley, making the effort as well.

The older she gets, Pfeiffer says of her views on diet, the more her focus and intent is geared toward living a longer life.

"Vanity is right under there," she admits, "but I have to say that it's a close second with wanting to live long."

Watch the full interview with Michelle Pfeiffer when she stops by "Piers Morgan Tonight" at 9 p.m. ET.