Imagine you're arriving at your local Denny's for breakfast. You sit down in the booth with your friends or family, and look over to see Dick Van Dyke across the restaurant with a group of men. 

That's pretty cool in itself! It's not everyday you see a celebrity at your local Denny's. But soon enough, the legendary performer randomly starts singing with an a cappella group, and your life has been made. 

It sounds like fantasy, but that's exactly what happened to some very lucky diners at a Los Angeles–area Denny's last Friday morning. 

Van Dyke arrived at the restaurant after appearing on the local talk show Good Day L.A. As the meal came to a close, he burst into song with his a cappella group, The Vantastix. Apparently, someone was a fan of the grits.

The impromptu performance of "Chitty Chitty Bang Bang" went flawlessly, with diners gathering to listen and capture the moment.

Van Dyke is currently on a promotional tour to promote his recent memoir, Keep Moving. The 90-year-old has certainly lived up to the title, with energetic appearances around the country this year. He's also performing with the Vantastix, with a concert scheduled later this month.

"Your perspective is everything," Van Dyke told Good Day L.A., saying he feels 50. "I wake up every morning ready to face the day."