Legendary actor Dick Van Dyke, and the rest of his a capella quartet The Vantastix, surprised an unsuspecting crowd at a Denny's restaurant in Santa Monica, California, on Friday 12 August after they burst into song, revisiting Van Dyke's beloved 1968 film Chitty Chitty Bang Bang.

Staged or not, the group appeared to have just finished breakfast in the diner when they began the rendition which had everyone up on their feet, recording the ditty with their camera phones.

Taking to both Twitter and Facebook the following day, Van Dyke – who played eccentric Caractacus Pott in the British musical – shared the video (below) of the performance alongside the caption: "Breakfast at Denny's, with a side of grits makes me want to sing!!"

When asked by a fan why the actor wouldn't rather go to a more local restaurant, Van Dyke enthusiastically replied: "No local restaurants that we know of serve grits. @DennysDiner serves grits daily!!"

Based loosely on Ian Fleming's novel Chitty Chitty Bang-Bang: The Magical Car and adapted by Roald Dahl and director Ken Hughes, the Oscar-nominated movie includes songs written by the Sherman Brothers. The story is of a down-on-his-luck inventor who turns a broken-down Grand Prix car into a ornate vehicle for his children, which in turn, takes them on a magical fantasy adventure to save their grandfather in an unusual, faraway land.

Formed in 2000, after meeting by chance in a coffee shop, Dick Van Dyke and The Vantastix have performed at a number of benefit and charity events, and released a children's album entitled Put On A Happy Face in 2009. Aside from Van Dyke, other members include Eric Bradley, who provides all-round vocals, tenor Bryan Chadima and bass Mike Mendyke.

Considering he's 90 years old, it's brilliant to see Van Dyke certainly hasn't lost his sense of showmanship... and rhythm. As of late, there have been rumours that the Diagnosis: Murder star is in talks to play a role in upcoming Disney sequel Mary Poppins Returns alongside Lin-Manuel Miranda and Emily Blunt. Judging by his Denny's performance, it might be a return to screen that many would welcome.

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