Prince Harry celebrated his 38th birthday Thursday with little fanfare as he continued mourning Queen Elizabeth II and the 25th anniversary of Princess Diana's death.

The Duke of Sussex had his "second saddest birthday" as his day consisted of visiting tributes to the late sovereign, who died Sept. 8 at the age of 96. Queen Elizabeth II was the longest-reigning monarch in British history with more than 70 years on the throne. She also held the title of the second longest-reigning monarch in the world.

"Today is Prince Harry’s birthday, and he’s been left at Frogmore Cottage with Meghan. Other members are off doing walkabouts and visiting floral displays in honor of the queen," Kinsey Schofield, royal expert and host of the "To Di For" daily podcast, told Fox News Digital. 

"Sadly, Harry’s birthday comes on the heels of the anniversary of Princess Diana’s death and now the queen’s. People are calling it his ‘second saddest birthday.’" 

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Prince Harry and Meghan Markle

Prince Harry (seen Wednesday) had his "second saddest birthday" Thursday as he celebrated turning 38 amid the death of Queen Elizabeth II and the 25th anniversary of the death of his mother, Princess Diana. (Getty Images)

Princess Diana died Aug. 31, 1997, in a car collision in Paris, France. She was known as "the People's Princess" despite her disdain for the press and life in the spotlight. She divorced Charles in 1996 with paparazzi ultimately chasing her to death. 

Harry's birthday wasn't even noticed by the official royal social media pages, including the accounts operated by his brother and sister-in-law, Prince William and Kate Middleton.

"Harry and Meghan are emotionally spent. The royal family typically wishes Harry a happy birthday on social media. A post had likely already been curated and approved prior to the death of the queen. Royal watchers are debating whether the lack of a post is out of respect for the circumstances or if the palace recognizes the real mix of reactions when it comes to the Sussexes presence in the U.K. right now."

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While William and Kate, the newly-appointed Prince and Princess of Wales, were seen meeting with mourners at Sandrigham, King Charles III spent the day reflecting on the loss of his mother.

"King Charles is taking the day off for rest and reflection," Schofield said. "Meghan is going to try to make the day special for Harry with a home-cooked meal and perhaps a sweet treat.

William, dressed in military uniform, and Harry, dressed in a suit, walk during Queen's procession

Prince William, left, and Prince Harry, second left, follow the casket of Queen Elizabeth II during a procession from Buckingham Palace to Westminster Hall in London, Wednesday, Sept. 14, 2022. The queen will lie in state in Westminster Hall for four days before her funeral Monday, Sept. 19.  (Vadim Ghirda)

Princess Diana held Prince Harry

Diana, Princess of Wales (1961-1997) with son Prince Harry during a holiday with the Spanish royal family at the Marivent Palace in Palma de Mallorca, Spain, August 1987. (Terry Fincher)

"Harry and Meghan are still very close to Princess Eugenie and Jack Brooksbank. I would not be surprised if the Brooksbank family stopped in to celebrate the king’s youngest son. We are also hearing that there are angry debates unfolding behind the scenes around Harry and Meghan’s children’s titles."

A major point of contention for the Duke and Duchess of Sussex remains at hand — if their children, Archie and Lilibet, will receive the "His/Her Royal Highness" titles bestowed on family with immediate royal bloodlines. 

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"Harry and Meghan are allegedly campaigning for HRH titles for their children for security purposes. King Charles does not agree as no member of their family is a working royal," Schofield said. 

Prince Harry and Meghan, the Duchess of Sussex, greet crowds outside Windsor Castle after Queen Elizabeth's death

Prince Harry and Meghan Markle met with mourners Sept. 10, 2022, after flying into the UK to be with the royal family. (REUTERS/Paul Childs)

In 2020, they departed from royal duties due to what they described as the British media's intrusion and racist demeanor toward their family. Markle revealed she felt suicidal before they decided to leave England and moved back to her home state of California. And Harry acknowledged there was tension with his father over his decision to not only step away from his royal responsibilities, but also for his marriage to the biracial actress.

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It's still unclear which of the children will be involved in the funeral on Monday, with speculation that William's eldest son George may be in attendance if any of the grandkids are.

"I don’t believe we will see the Sussex children flown into the U.K. due to the ongoing tug of war over titles," Schofield said. "Harry has got to make his point that he feels his children are not safe there."