Betty White's Secret to Longevity: Hot Dogs?

At 91, Betty White is old enough to be your grandmother (OK, possibly your great-grandmother). So what's the secret to her longevity?

It's probably not her daily diet.

The "Hot in Cleveland" star noshes on a hot dog and french fries for lunch. Every day. And that's not her only indulgence; Betty snacks on Starbucks blueberry muffins when she arrives at work and makes a point of keeping her dressing room stocked with Red Vines.

But it doesn't seem to be slowing her down. Now in her fifth season with the TV Land series, Betty is America's reigning TV sweetheart — a late-to-bloom hipster who had everyone from Blake Shelton and Sarah Silverman to Bill Clinton and Bill Cosby show up to party when she turned 90.

[Related: Check Out 'Hot in Cleveland' Photos]

And today, she was all ours! Betty shared a day in her life, snapping pics on the set of "Hot in Cleveland" for our Yahoo! TV Instagram account. But it wasn't just another day at work for the actress — the show is prepping for its first live episode; airdate June 19.

That means Betty rubbed shoulders with guest stars William Shatner, Brian Baumgartner, and Danny Pudi at a very special table read, alongside regular cast members Valerie Bertinelli, Jane Leeves, and Wendie Malick.

[Related: 'Mary Tyler Moore Show' Ladies on 'Cleveland' Stint: 'We Don't Have to Fake It']

She also shared photos of some of her favorite animals, real and fake! The animal advocate, who raises money for the Morris Animal Foundation, decorates her dressing room with artwork by Koko the gorilla and stuffed animals given to her by friends and crew members. (Betty says goodnight to each animal before she leaves every day.)

In case you didn't catch Betty's Instagram takeover as it was happening, we've chosen our favorite snapshots for this exclusive photo gallery. Check it out and be sure to follow Yahoo! TV on Instagram!

"Hot in Cleveland" returns with a live summer premiere on Wednesday, 6/19 at 10 PM on TV Land.