• Queen Elizabeth will be missing her husband Prince Philip's companionship "deeply," a report says
  • Royal biographer Sally Bedell Smith said the impact on the Queen of the loss of a confidant should not be underestimated
  • The monarch reportedly has been inviting friends over for dinners and is rarely alone at Windsor Castle since her husband's death

Queen Elizabeth II marked New Year's without her husband Prince Philip for the first time in more than 70 years.

The 95-year-old monarch spent the holiday season at Windsor Castle for the second year in a row due to the pandemic, but this was her first Christmas and New Year's without her husband of 73 years, the Duke of Edinburgh, who died in April at age 99.

"She'll be missing his companionship deeply," an unnamed source told People. "But she is a stoic person."

The Queen, who had enjoyed a golden twilight with Prince Philip in the months before he died at Windsor Castle, takes comfort from the fact that she and the members of the royal family were able to say their goodbyes in person, sources told the outlet.

Royal biographer Sally Bedell Smith, author of "Elizabeth the Queen: The Life of a Modern Monarch," said she believes the Queen had been prepared for the death of her husband, who struggled with multiple health issues over the years.

"The way he died, so very peacefully, there was a natural way to how he left. I am sure she had plenty of time to prepare for it," Smith explained.

But she added, "I don't think anyone should underestimate that, however resilient, however faith-based and however strong she is, this is a confidant who is no longer there."

Since losing her husband, Queen Elizabeth has been spending time with friends, inviting them over for dinners and evening TV-watching. The monarch also has the company of personal aide Angela Kelly, longstanding footman Paul Whybrew and other staff inside the "bubble" at the castle, according to sources.

"Those who are in it cherish their place. They are a support for the Queen and someone that she can have a laugh with and with whom she can talk about the issues of the day," an anonymous insider told People.

"Whatever her private grief is, she wants to get on in as cheerful a way as possible," an unnamed "close" insider added.

Christmas was "a bit of a struggle" for Queen Elizabeth without Prince Philip by her side, Us Weekly previously reported, citing an unnamed source.

According to the insider, it didn't help that she wasn't able to spend the holiday with her whole family.

Prince William and Kate Middleton celebrated Christmas at their countryside home Anmer Hall in Norfolk, England, with their kids — Prince George, 8, Princess Charlotte, 6, and Prince Louis, 3 — after the Queen changed her holiday plans. Prince Harry and Meghan Markle, meanwhile, marked the holiday at their Montecito, California, mansion with their children, Archie, 2, and 6-month-old Lilibet.

However, the insider said Queen Elizabeth is "not one to wallow in self-pity and kept her chin up."

Queen Elizabeth was joined by her son Prince Charles and his wife Camilla, Duchess of Cornwall, at Windsor Castle after the monarch canceled the royal family's plans to gather at her Sandringham Estate for the holiday amid a rise in COVID-19 cases across the U.K.

But while the Duke and Duchess of Cambridge were not able to spend Christmas with the Queen, Prince William reportedly "liaised" with Prince Charles and Princess Anne, who was isolating through the holiday, to organize a group Zoom call with the monarch. The virtual reunion not only "brightened up" the Queen's day but also helped make Prince George, Princess Charlotte and Prince Louis' holiday, the source said.

Meanwhile, a crossbow-wielding intruder was arrested on suspicion of breach or trespass of a protected site and possession of an offensive weapon after breaking into the grounds of Windsor Castle last week while the Queen and her family were celebrating Christmas.

U.K. police are currently investigating the incident as well as a video linked to the 19-year-old suspect in which he threatens to "assassinate" the Queen.

Queen Elizabeth II had an overnight stay in hospital after a packed schedule in early October
Queen Elizabeth II had an overnight stay in hospital after a packed schedule in early October POOL / Victoria Jones