Prince Harry and Meghan Markle are welcoming their first child in a few weeks, and the Duke of Sussex has a very important royal duty to perform in the ward as soon as Baby Sussex comes out. This duty has to do with Queen Elizabeth, who, by royal tradition, should be the first to be told the news before any other royal.

Traditionally, a royal father uses an encrypted phone to let the head of the family know the sex of the baby. Prince Harry is not an excuse in this tradition. As soon as the new royal baby arrives, the first thing that Prince Harry has to do is to give Queen Elizabeth a ring and tell her the exciting news.

According to royal historian Kate Williams, Prince Harry must be in the ward with Meghan as she gives birth and make it a point that his encrypted phone is with him while the Duchess of Sussex is on labor. In the ITV documentary “Secrets Of The Royal Babies: Harry And Meghan,” Williams said Prince Harry would not pace the corridor outside while Meghan gives birth but would be right there inside the ward with her.

“He’ll be there doing yoga moves with Meghan,” she joked. “What normally happens is that there is an encrypted phone that cannot be tapped and he will tell her whether it’s a girl or boy,” she added.

Although it would make more sense to inform Prince Charles first because he is Prince Harry’s father, based on royal protocol, Her Majesty must be the one to know first because she is the head of the royal family. Prince William followed the same tradition when Kate Middleton gave birth to her children. So right after Prince George came out, the Duke of Cambridge immediately called the Queen through an encrypted phone line to let her know that the royal baby had finally arrived. After informing Queen Elizabeth, he gave Kate’s family a ring.

It remains to be seen how Prince Harry and Meghan Markle will inform the public of Baby Sussex’s coming. In the past, the royal family announced royal births by placing a framed document on an easel in the forecourt of Buckingham Palace.

Prince Harry Prince Harry, Duke of Sussex, talks with guest during the Veterans' Mental Health Conference at King's College. WPA Pool/Getty Images