Queen Elizabeth II dropped by at Prince William and Kate Middleton's residence to visit Prince Louis.

On Thursday, the Queen was spotted leaving the Duke and Duchess of Cambridge's home. She was wearing a pale blue boucle ensemble and paired it with sunglasses. She was seated in the back of her chauffeured car.

A day prior to the Queen's visit to Prince Louis, his grandmother, Carole Middleton, dropped by Kensington Palace. The Duchess of Cambridge's mom was seen wearing a pair of dark oversized shaded a button-down floral dress. She paired her get up with yellow block heels.

Prince William and Middleton's youngest turned a month older on Wednesday. This could be the reason his grandmother and great-grandmother paid him a visit.

The Duke and Duchess of Cambridge welcomed Prince Louis on April 23 at St. Mary's hospital.

"Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 1101hrs. The baby weighs 8lbs 7oz. The Duke of Cambridge was present for the birth. Her Royal Highness and her child are both doing well," Kensington Palace announced following Middleton's delivery.

The Duchess of Cambridge had a speedy recovery. In fact, she was spotted out and about seven hours after giving birth for her newborn's public debut.

Middleton is known for her speedy hospital exits. When she delivered Prince George and Princess Charlotte she was in and out of the facility for only 12 hours.

According to a source, the Duchess leaves the hospital immediately to avoid interrupting its services. She knew that her presence would cause a frenzy. In addition, the media and photographers usually camp outside to capture a photo of them with their newborn.

Prince William and Middleton opted to leave Prince Louis at home during the royal wedding.

Royal commentator Richard Fitzwilliams had already predicted this. According to him, it's the best thing to do so the guests' attention would not be divided between the baby and the bride and groom.

"They certainly won't bring the baby to the wedding, this will ensure that the focus is on Harry and Meghan as of course it should be," Fitzwilliams said.

Also, according to a professional, it's best if babies at Prince Louis' age to stay at home for health reasons. "In truth, a newborn baby could go on a plane or be out in public even the day after they’re born. We prefer though, that they not for the first two months because the worry is they’re going to get sick," Dr. Robin Jacobson told Town & Country.

Queen Elizabeth II Queen Elizabeth II visited Prince Louis. Pictured: Queen Elizabeth II attends the Chelsea Flower Show 2018 on May 21, 2018 in London. Photo: Getty Images/Chris Jackson.