A breast cancer scare and a close friend's cancer diagnosis led Renée Zellweger to her latest role – TV producer.

In 1996, just after she shot to superstardom in Jerry Maguire, the actress found two lumps in her breast. They turned out to be benign, but, "I had a weird couple of days waiting for the phone call," she says in the October issue of Self magazine.

Breast cancer touched Zellweger's life again when her close friend and publicist, Nanci Ryder, was diagnosed with the disease. Ryder beat it when her friend, philanthropist Lilly Tartikoff, took her to see Dr. Dennis Slamon, the renowned UCLA researcher who worked against all odds to help develop the life-saving breast cancer drug Herceptin.

So when Zellweger – who went onto become an anti-cancer activist – was asked by her Chicago producers Craig Zadan and Neil Meron to executive produce the Lifetime movie, Living Proof, about Slamon's fight, she jumped at the chance.

Zellweger turned out to be a mover and a shaker in her first foray as a TV producer, Zadan told PEOPLE at the movie's New York premiere Wednesday night.

"Whenever we would need to get to so-and-so, she'd say, 'I'll send an email.' She could get to anybody because if you get a personal email from Renée Zellweger, you take it very seriously," says Zadan. "She helped put this movie together and emailed practically all the stars in the movie to see if they would be in it."

Renée Zellweger Reflects on Cancer Scare - TV News, Renee Zellweger : People.com