Royals Queen Elizabeth Spends a Night in the Hospital After Canceling Visit to Northern Ireland Queen Elizabeth was released from the hospital on Thursday and "remains in good spirits," according to Buckingham Palace By Gabrielle Chung Published on October 21, 2021 06:37 PM Share Tweet Pin Email Queen Elizabeth. Photo: Steve Parsons/AP/Shutterstock Queen Elizabeth spent Wednesday night in a hospital after canceling a trip to Northern Ireland under medical advice from her doctors, according to Buckingham Palace. In a statement issued on Thursday, the palace said that the 95-year-old monarch "remains in good spirits" following the overnight stay, during which she underwent "preliminary investigations." "Following medical advice to rest for a few days, the Queen attended hospital on Wednesday afternoon for some preliminary investigations, returning to Windsor Castle at lunchtime today and remains in good spirits," the statement read. The Queen was admitted to the hospital as a cautious approach by her medical team. She was back at her desk on Thursday afternoon, undertaking light duties. Queen Elizabeth II. GEOFF CADDICK/AFP via Getty Images Queen Elizabeth Cancels Planned Visit to Northern Ireland Last Minute on Advice of Doctors News of the Queen's hospital stay comes a day after the palace announced that the monarch would not be visiting Northern Ireland as previously planned. The two-day visit was to mark the 100th anniversary of Northern Ireland. "The Queen has reluctantly accepted medical advice to rest for the next few days," a statement released on Wednesday read. "Her Majesty is in good spirits and is disappointed that she will no longer be able to visit Northern Ireland, where she had been due to undertake a series of engagements today and tomorrow." Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! The Queen last made a public appearance on Tuesday night, when she — alongside Prince Charles, Prince William and other royals — welcomed international business and investment leaders at the castle for a Global Investment Summit reception. Guests included Bill Gates and U.S. Special Presidential Envoy for Climate John Kerry. Ahead of the reception, the Queen released the foreword she wrote for the official brochure, which highlighted previous examples of British innovation and illustrated how people's ability to connect has helped them navigate historic challenges. RELATED VIDEO: Queen Elizabeth Steps Out in Public with a Cane for the First Time in 17 Years The COVID pandemic "has often threatened what we have all previously taken for granted: the opportunity to be, work, and grow together," she wrote. "Yet, in the face of these challenges, I have been inspired by countless stories of overcoming these hurdles. We have learned to connect with each other through innovative technologies and ... achieved scientific breakthroughs faster than was ever expected." Tuesday's reception was another important event in support of the royals' continued focus on climate issues ahead of the COP26 U.N. Climate Change Conference in November.