Kate Middleton Prince Harry and Meghan Markle
Kate Middleton, Meghan Markle and Prince Harry arrive for the Royal Family's traditional Christmas Day service at St Mary Magdalene Church in Sandringham, Norfolk, eastern England, on December 25, 2018. Getty Images/Paul Ellis

Royal fans are eagerly anticipating news of the arrival of Prince Harry and Meghan Markle’s first child together. However, a new report claims that Kate Middleton could potentially be the key to determining just when the Duchess of Sussex will welcome her baby into the world.

According to Express UK, the length of Markle’s maternity leave could be an indicator of when her due date actually is, and if she’s modeling her leave after her sister-in-law, then her due date could be a special one for the royal family as a whole.

The website reports that when Middleton was pregnant with Prince Louis, she began her maternity leave on March 22, 2018. Exactly one month and one day later, on April 23, she welcomed her son. If Markle scheduled her maternity leave to begin one month and one day before her own due date, then that means she could be expected to welcome her child on April 21—the same day as Queen Elizabeth’s own birthday.

There has previously been speculation that Markle could give birth on this special date since she was due in late April or early May. It was also speculated she could share a birthday with Prince Louis on the 23 or Princess Charlotte on May 2. She could also give birth on April 30, the same day that Middleton and Prince Wiliam will celebrate their 8th wedding anniversary.

However, it’s also being cautioned that even if Markle is mirroring Middleton and may have a due date on the 21st, it doesn’t mean that she will give birth then. Middleton’s pregnancy with Louis was her third, while this is Markle’s first—and firstborn babies generally have a 15-16 percent chance of being born late.

According to Ladbrokes, the odds of Markle giving birth on the 21st are 7/1. Sharing a birthday with Prince Louis stands at 6/1 odds, and an early May birth is currently at 7/2. The odds that she gives birth on Middleton and William’s anniversary are 4/1.