A 'Ray of Light': Princess Kate Is 'Resolutely Cheerful' With Wales Kids and Prince William on Royal Wedding Anniversary

Prince William and Catherine, Princess of Wales celebrated 13 years of marriage on Monday, April 29, which has left the future queen in a state of contentment

"She remains a ray of light in what can often be a suffocatingly stuffy environment behind palace walls," royal author Christopher Andersen told an outlet.

"When they celebrated their 12th anniversary by releasing a photo of themselves smiling broadly on bicycles, no one could have imagined that a year later both Kate and the king would be battling cancer," he added. "More than ever, William and Kate have reason to include the children in everything and keep the prevailing mood as upbeat as possible. Despite her challenges, Kate is incapable of being anything but resolutely cheerful around George, Charlotte, and Louis."

Although it is not known exactly how the monarch and queen consort-in-waiting celebrated their special day, numerous analysts and royal insiders were hard at work beforehand trying to predict the duo's plans.

"We've got the anniversary of William and Catherine on the 29th of April," former royal butler Grant Harrold told Spin Genie on Friday, April 26. "With everything going on with Kate, that won't be a public thing, that's going to be very private. Behind closed doors, I'm sure William will work to make sure she's spoiled."

He added: "It's possible William might cook, he's quite a good cook so it's possible he might do a little meal or something. Again, it's just going to be a private affair between the two of them. Once again, there'll still be an exchange of gifts, I have no doubt they will give each other a gift, and I've no doubt they will exchange cards."

The former palace aide then revealed the pair's possible dining plans and shared: "I've no doubt that there'll be a special meal for them, whether it's a meal where they invite friends and family, or just them. Again, well-wishers will pass on their love with cards."

Kate first met William when they were students at St Andrews University in Scotland during the fall of 2001. The two teenagers took their relationship slow, and it was nearly a full decade after they met, including a brief breakup in 2007, before the commoner officially became a princess at their lavish April 29, 2011, Westminster Abbey wedding. Many royal analysts have come forward in the past few days to explain just how much the two mean to one another.

"There is no question that William has been Catherine’s rock. Even with William’s busy schedule, he is the constant in her life, and she is at the heart of his," royal author Robert Jobson dished.

Us Weekly reported on the expert opinions.