Big hint Meghan Markle is further along in pregnancy

Meghan, Duchess of Sussex meets with a local surfing community group, known as OneWave, raising awareness for mental health and wellbeing. Photo / AP

It has been widely reported that Meghan Markle is 12 weeks pregnant, but a social media slip-up from earlier this week appears to have revealed her real due date.

On Tuesday, the Duke and Duchess of Sussex attended an afternoon reception at Admiralty House.

At the event Meghan was photographed chatting to Missy Higgins, doting over the singer's nine-week-old baby Luna, reports news.com.au.

Later that day Higgins shared an Instagram post of her meeting with the Meghan, detailing their conversation and praising the Duchess for tackling a day of engagements while four months pregnant.

View this post on Instagram

What an honour to meet the beautiful Duchess today! She was such a sweetheart. I said I felt sorry for her having to do all these meet-and-greets while 4 months pregnant! What a trooper. Prince Harry was gorgeous too, a real charmer. He squeezed Luna’s legs and said “who’s this little cutie?” Looking forward to telling Luna she slept through it all one day 🤣 👑 💙👸🏼🤴 ........ Earrings @biancamavrick Top @kuwaii ........ #royalbaby #meghanmarkle #royaltour

A post shared by Missy Higgins (@missyhigginsmusic) on Oct 16, 2018 at 3:30am PDT

Higgins' post of her conversation with Meghan appears to reveal her real due date, contradicting reports from multiple media outlets that Meghan is three months pregnant and has recently had her 12 week scan.

But if Meghan was further along in her pregnancy it would also explain why she has been able to tackle such a hectic tour schedule with ease (apart from a few secret breaks).

Meghan gave the world the first glimpse of her bump on Monday. Photo / Getty Images

Many pregnant women still experience morning sickness between the 12-14 week mark, meaning a full day of engagements would have been difficult for Meghan if she was still experiencing symptoms.

Kensington Palace confirmed on Monday that Meghan and Harry were expecting their first child in the UK spring, which runs from March 20 to June 21.

It came after weeks of speculation that Meghan was pregnant, with the Duchess of Sussex wearing a loose fitting coat at Eugenie's wedding last week and clutching a purple folder in front of her stomach when she arrived in Sydney on Monday.