It will not be unusual for the Duchess of Cambridge [VIDEO] to disappear from the public eye until October. That's because it 's a royal tradition that new mothers are entitled to a six-month maternity leave. That means they are excused from carrying out royal duties during that time.

We saw Kate Middleton [VIDEO] at Prince Harry and Meghan Markle's wedding on Saturday, May 19 just a few weeks after giving birth to Prince Louis. That was a special exception because it was a family outing and not an official engagement.

She and Prince William were absent from Prince Charles' 70th birthday celebration on Monday. Prince William was speaking at an event for the Manchester Arena bombing victims.

Kate appeared at neither one of the events, but she did not break any rules because her maternity leave continues. It seems as though she will take advantage of being on maternity leave and will be selective in the events she will attend.

Option to pick and choose

Royal biographer Duncan Larcombe explained that Kate Middleton has the option to pick and choose which affairs she will attend. She will be permitted to attend or choose not to appear in public until next fall. The Duchess of Cambridge appeared in public until her eighth month of pregnancy.

She went on maternity leave on March 22 to prepare for the delivery of the new arrival. That means her maternity leave started an entire month before Prince Louis was born on April 23. Therefore, she had five months left after his birth.

Extended maternity leave

It was originally believed that Kate would take the entire six months and not take on any royal engagements until the fall.

Now it is believed that she might extend the six months to a longer period of time because new reports indicate that she might have gone back to work too soon after giving birth to Prince George and Princess Charlotte.

If the Duchess of Cambridge does get an extension on her maternity leave, she might not appear for royal duties until close to the end of the year. No one could blame her if she takes extra time. After all, she and Prince William have three children ranging in ages from one month to four years.

Upcoming family affair

Another family affair is coming up on June 9. The Duchess of Cambridge might attend that event. It is Queen Elizabeth's official birthday celebration called "Trooping of the Colours." You might remember the queen celebrated her actual 92nd birthday on April 21. That birthday celebration was a private affair with family members.

The upcoming birthday celebration is for Queen Elizabeth's reign for 66 years. It is a public and formal event that includes a parade with 1,400 soldiers, 200 horses, and 400 musicians.