Now this is Supercalifragilisticexpialidocious! Legendary actor Dick Van Dyke kicked off his 90th birthday this past Saturday, December 12, in L.A., by singing Mary Poppins songs with a flash mob.

The actor, who starred opposite Julie Andrews in 1964 Disney classic Mary Poppins as Bert, the title character's love interest, was at The Grove when a flash mob performed in the lower level of the mall. The performers, dressed like chimney sweeps just like Bert, delivered his character's trademark songs, including "Step In Time," "Chim Chim Cher-ee," "Jolly Holiday," and "Supercalifragilisticexpialidocious."

At the tail end, he joined the group and delivered "Let's Go Fly a Kite" from Poppins. Then, the crowd sang the birthday song to the actor.

Van Dyke posted a video from the wild excursion, and wrote: "I am very grateful that at 90 years old, I can still go out and play."

In an interview with CNN last month, the actor shared how he maintains his youthful spirit. “Don’t do anything that isn’t fun,” he advised. “I may have reached that point in life where I don’t have to do anything that isn’t fun.”

He joked about his age. "It’s such a surprise. I remember at 80 I said this is acceptable, this is just fine," Van Dyke said in the interview. "I didn’t know it was a very slippery slope after that."

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