Kate Middleton has recently been the target of controversies after she was noticeably missing in several public events. As the rumors suggested that the Duchess of Cambridge was battling postpartum depression, recent issues emerged sparked imminent divorce between Middleton and husband Prince William.

Recently, Kate Middleton, who gave birth to Prince Charlotte on May 2, has become unusually reclusive from the prying public. But in order to take the Duchess out of her rural isolation in Norfolk, Daily Mail revealed that Queen Elizabeth is reaching out to Kate to invite her and Prince William to her Scottish home, Balmoral. The royal couple will help her celebrate her landmark day on Sept. 9 as the nation's longest-reigning monarch, surpassing her great-great-grandmother, Queen Victoria.

"The Duke and Duchess of Cambridge will be with the Queen at Balmoral on September 9," Daily Mail's Sebastian Shakespeare was told. "They will attend a family dinner that Her Majesty will give that evening."

Kate Middleton's invitation came after Prince William wrote a moving tribute in the foreword of Queen Elizabeth's biography, "Her Majesty," written by former Foreign Secretary Douglas Hurd and will be published on her landmark day.

The upcoming Balmoral visit will be Kate Middleton's first major social event she'll be attending after ditching the wedding of Prince William's friends, estate agent Bear Maclean and socialite Daisy Dickson, in Devon, a month ago. According to Inquisitr, the bride and groom have not anticipated the Duchess' absence. Since she didn't make it, the 33-year-old Duke of Cambridge turned up with his sister-in-law, Pippa Middleton instead.

Since their wedding in 2011, Prince William and 33-year-old Kate Middleton attended dozens of weddings. But in the next two years, the Duchess went to none while the Duke has been to at least five weddings alone. The reason? Aside from putting her children first, veteran royal photographer Mark Stewart suggested another theory.

"They didn't like the idea of upstaging the bride and groom — they wanted it to be about the couple getting married and not themselves and she will be aware that William is the royal and therefore they do get a member of the royal family there," Stewart said.

Meanwhile, there have been several signs that Kate Middleton and Prince William are facing marital troubles. For one, Movie News Guide noted that the Duchess was reportedly jealous of Prince William's ex Olivia Hunt, who has been recently engaged to high-profile barrister, Nicholas Wilkinson.

Since Prince William seemed to have been affected by the engagement, it has allegedly ignited a fight between the couple. Celeb Dirty Laundry, however, claimed that the Duke didn't want to marry Kate in the first place, instead he wanted Isabella Calthrope, who have moved on and married Sam Branson.

Despite the alleged infidelities, postpartum depression and feud with Queen Elizabeth, the royals have been quick to dispel the rumors. Prince William and Kate Middleton, who are proud parents of Prince George and Princess Charlotte, have both maintained a happy and united public image.

So, are Kate Middleton and Prince William heading for splitsville? Or are the imminent royal divorce news simply speculations suggesting the royal's failed marriage?