Speaking to People about her partnership with Grove Collective, which makes environmentally friendly products for the home, Drew Barrymore detailed where her passion for living green came from. "I made a promise to my best friend, Cameron Diaz, that I would become someone who she had been pushing me to be my whole life, which was environmentally aware, conscientious, and living a certain lifestyle that was sustainable," she said. 

"She's been saying this since the '90s to me," the beloved nineties star continued. "Once I started living that way and really committing, [I] saw the world differently and it made me put it all into practice and action." Barrymore also shared that, inspired by the passion her friend has always had for protecting the planet, she has made several changes in her own life, from giving up her "favorite thing" (ziplock bags) to making sure she turns off the water while brushing her teeth. 

And in larger ways too, including her partnership with Grove Collective. Barrymore has been doing her best to make Diaz proud throughout their decades-long relationship. And it's a lot to live up to; Diaz has been a lifelong advocate for sustainability and the environment thanks to her Californian upbringing, where she saw her father work on pipelines in Long Beach (via TIME).