• Meryl Streep says her approach to juggling work and family as a grandmother comes down to one simple idea.
• The actor said it involves "grabbing seconds" and appreciating every moment she has with her six grandkids.
• The idea of making the most of what she can extends to her career as well, Streep added.

Meryl Streep, 76, says being a working grandmother is simple: Take whatever time you can get, and don't waste it.

In a joint Vogue interview with Anna Wintour published on Tuesday, the actor spoke about how she carves out time for family despite her demanding career.

"It's just grabbing seconds, just grabbing everything you can of them, with the knowledge of how completely fleeting it all is and how rapidly time goes. This is what my mother said to me, and I said, 'Yeah, yeah,'" Streep told Greta Gerwig, who moderated the interview. "It's the longest, shortest time. And you can't get anything back. So take as much as you can…. I find it divine."

"The Devil Wears Prada" star has six grandchildren, ages 1 to 6.

"I can't even talk about how much it means to me that my kids give me as much time as they do with their kids. The only thing is that they're on two coasts, so I'm in the airplane a lot," Streep said.

She said that mindset of making the most of her time also shapes how she approaches her career.

"Tom Stoppard said, 'You've got to shift your weight.' You're always, always on unstable ground. It's so uncertain being an actor. You're chronically unemployed. And then there's no sort of climb, because fame is something you have in a second," she said.

Stoppard, the acclaimed playwright and screenwriter, was once her partner.

Still, she said building a meaningful body of work requires patience and self-belief.

"That takes time, and you can't do it at home by yourself — it's not like writing or composing. I don't think: I love this job. I'm going to have this job for a long time. I think: This is the world. The unstable world. Everything changes and it's about learning to sort of be prepared for that," she said.

Streep said she drew inspiration from Wintour's leadership and curiosity as she reprised her role as Miranda Priestly in "The Devil Wears Prada 2," which is set to hit theaters May 1.

That idea of staying engaged also shapes how she thinks about aging.

"That's the key, I think, to being alive: Always breaking new water. Always breaking the waves. And we're not done yet," Streep said.

This isn't the first time Streep has spoken about managing work and family life. In a 2008 interview with Good Housekeeping, she said it requires constant effort.

"Motherhood, marriage, it's a balancing act," Streep said. "Especially when you have a job that you consider rewarding. It's a challenge but the best kind of challenge."