Have you ever ordered a milkshake from McDonald's, taken a sip and thought it tasted like a completely different flavour?

This I've found has often been the case whenever I've gotten a vanilla milkshake, as it often tastes like banana instead.

I never really knew why... until now.

A TikTok user named Dessy Joseph from the US has gone viral on the social media platform after sharing a number of McDonald's 'secrets' she learned while working there.

One of those 'secrets' is all about the milkshakes and why they sometimes taste like the wrong flavour.

She revealed all after a follower messaged her to ask why there was "red stuff" at the bottom of their vanilla milkshake.

A McDonald's drink
Has your milkshake ever tasted of two flavours? (stock photo)

In the clip, she explains: "Why sometimes this happens is because the shake machine will pour out a little bit of the previous flavour before it pours the new flavour.

"So sometimes you'll order a vanilla shake and you'll see the bottom is a little green because it's Shamrock shake season, or maybe it's a little brown, or your chocolate shake tastes a little like strawberry.

"Strawberry shake tastes like a little chocolate? It's just leftover syrup from the drink before."

Dessy goes on to add that if you're allergic to one of the flavours, make sure you mention it before ordering your drink, so they can ensure the syrups don't get mixed up.

Dessy on TikTok
Dessy shares 'secrets' she learned at McDonald's

More than 92,000 people have watched the video, with it garnering over 14,000 likes.

One person replied: "My friend got a strawberry milkshake and half of it was chocolate."

Another said: "Ewwww."

Someone else wrote: "You're supposed to use water to clear out between shakes."

A different user added: "She speaks truth. I used to be a manager."

This comes after another TikTok user went viral for sharing what the different coloured barista aprons really mean at Starbucks.

Eloise Fouladgar explained: "So if you have a green apron on this just means you're a standard barista, maybe you just started working there, it's kind of the basic apron that everyone gets."

She went on to say that if you see someone wearing a black apron, this is the employee you want to make your drink, as they're much more skilled.

Eloise branded those with a black apron the "coffee masters" as they make "amazing coffee".

A spokesperson for Starbucks later confirmed this is true and revealed there are several other aprons as well.

They said: "Customers can look out for the coloured aprons worn by our baristas, as these will tell you if you’re being served by: a barista (green), a Starbucks Coffee Master (black), the best barista in a particular country (brown) or a winner of Starbucks annual Barista Championships in Europe, Middle East and Africa (purple). Red aprons are worn to match Starbucks Red Cups, a sign that Christmas is coming!"