Why Princess Diana insisted on buying her own groceries

Just about every woman enjoys a good shop every now and then, and Princess Diana was no different it seems.

But while we usually picture royalty strolling through exclusive designer stores or shopping after hours in lavish boutiques, Diana's shopping was much more normal.

In fact she used her trips to the grocery store as a way of staying grounded and keeping herself in touch with the normal life she had known before she married into the royal family.

The princess used to make regular trips to Marks & Spencer on Kensington High Street in London, her former protection officer Ken Wharfe speaking in the new documentary By Royal Appointment: Shops Serving The Queen.

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"It was bizarre, to see the princess walking down the aisles picking up from the freezer a bag of McCain chips, or burgers off the shelf," he said.

The sight of a royal family member in a grocery store is rare, as it's considered somewhat un-royal for them to do their own shopping.

Instead most of the royals have their groceries delivered, and it's likely that many blood royals have never done a weekly grocery shop.

Yet Diana was committed to her trips to the store, just as she was devoted to giving her sons Prince William and Prince Harry as normal a childhood as possible.

Apparently one that included McCain chips and frozen burgers!

"I used to think, why do you need to do this? Because there must be stacks of it back at Kensington Palace," Wharfe said of the princess' shopping trips.

"But it was this thing about Diana, being in touch with normality and reality."

And it seems that daughter-in-law Kate Middleton followed suit, having been spotted doing her own shopping on Kensington High Street several times since she joined the royal family in 2011.

Expectant parents Harry and Meghan Markle also reportedly do their own shopping in an attempt to keep a bit of normalcy in their lives, Harry telling Newsweek that he is "determined to have a relatively normal life."

It's a principle his mother taught him and one that he will likely pass down to his own children, his first child with Meghan due any day now.