People baffled by bizarre detail in Gwyneth Paltrow's birthday tribute to daughter Apple

Birthday celebrations are always a time of the most, joy, but Gwyneth Paltrow's post created a little more than it bargained for when it included a strange reference.

An inside joke? This is what people may be asking themselves after seeing what actress Gwyneth Paltrow posted to her Instagram page yesterday (15 May) to celebrate her daughter, Apple Martin, turning 20 years old.

Apple is the eldest child of the Goop founder and her ex-husband, Coldplay frontman, Chris Martin - whom she split from in 2014 after being married since 2003.

The former couple also share Moses Martin, 18.

Both Apple and Moses have ventured in their dad's footsteps by becoming singers, however, many people have noticed the striking resemblance between Gwyneth and her children.

In celebration of her daughter's big day, Paltrow posted a few pictures of Apple as a toddler, as well as a recent picture.

Writing to her 8.5 million followers, she said: “Happy 20th birthday, @applemartin. How can it be that you are 20 today? It feels surreal!

"You are the most extraordinary, the most hilarious, the most brilliant.. I love your WWII insights as much as I love your physical comedy.

"You are the most fun to be with and you have always been. From those days when it was always you and me to now, you are my lil ride or die.

"You are everything to me and I am so proud of you. Have the best day, my peanut. Mama.”

While many commenters were quick to wish Apple a happy birthday, one part of Gwyneth's post left a few people pretty baffled.

One person wrote: “Her WHAT insights?????”

You read it right, according to Paltrow, her 20-year-old daughter has 'insights' on the World War II - whatever that means.

While someone else asked: “is she pro or against WWII?”

Apple herself also commented on her mother's post: "You are the best mama a girl could ask for. I am so lucky the universe gave me to you," - seemingly glazing over the 'WWII insights' part.

However, the Iron Man star has also created a similar post for her son’s 18th birthday celebration too, writing: “I am so proud of who you are. I love your sensitivity and brilliance and quiet humor.

"I admire how deep you go into areas that interest you, becoming an expert in synths from the '80s and the French new wave.

"I love how much you love the people you love, but also how internal you are.”

Perhaps it's a yearly tradition?