Prince George, as we know, is starting “big school” this week, at Thomas’s Battersea in London — a short drive away from his family home at Kensington Palace.

And while his parents had planned to drop him off at the gates, it appears his beloved mum may be forced to skip the monumental occasion.

Kensington Palace announced Monday that the Duchess of Cambridge is in the early stages of her third pregnancy, and is once again suffering from Hyperemesis Gravidarum — the same condition she battled while pregnant with George and two-year-old daughter, Charlotte.

Speaking with The Daily Mail, an anonymous royal expert said her attendance at the school would be “highly unlikely” due to the debilitating condition.

“It’s looking highly unlikely now,” the source said. “The Duchess wanted more than anything to be there. It’s a big day for her son. But she has been really very sick this week.”

Prince William has also spoken out about an “anxious start” to his wife’s pregnancy.

“We need Catherine to get over this first bit and then we can start celebrating,” he said at a National Mental Health and Policing Conference. “ It’s always a bit anxious to start with, but she’s well.”

He added: “There’s not much sleep going on at the moment.”

What’s more, the beloved royal needed to pull out of two public engagements on Monday and Tuesday.

Of course, there’s hope yet — the royal couple have until tomorrow morning (local time) to make their decision.

WATCH: Prince George and Princess Charlotte steal the spotlight wherever they go. Post continues…

Young George, who turned four in July, has been enrolled in one of three reception classes at the co-educational outpost, and he will join a mixed class of boys and girls at the $AUD28,607 per year school.

Upholding a set of core values – kindness, courtesy, confidence, humility and learning to be givers, not takers – the elite school holds an impressive record of senior school entrance and scholarship successes. In fact, the Tatler Schools Guide says the “cream of the Battersea crop rises to the likes of Eton and Wycombe Abbey”.

Earlier this year, William and Kate stepped out for the school’s orientation day.

“They were there just chatting with the other parents. They seemed very sweet and normal,” a source told E! News. “George was there as well. He met his new teacher.”

“The kids went into their new classrooms for an hour to meet their new classmates and hear from their teachers,” the insider continued. “During that time, the parents met the head of the school and were given a welcome talk where they were told the exact specifics of the children’s first day.”

The school, which is just a stone’s throw from their royal residence, currently has 544 day pupils, aged between four and 13.

We can’t wait to see the royal tot in his school-best for the big day!

Celebrity Candice Mehta-Culjak