The Princess of Wales is expected to carry out her first major engagement since undergoing an operation when she reviews trooping the colour in June.

Catherine has been recovering from abdominal surgery for the past seven weeks and, while no confirmed date has yet been given for her return to public duties, she was due to be recuperating until at least Easter.

The news of her purported first engagement was revealed on the British army’s website, where tickets for the 8 June event are being advertised alongside a notice that reads: “Reviewed by her Royal Highness the Princess of Wales.”

The spectacle will take place the weekend before the main trooping the colour ceremony, which is normally reviewed by the monarch.

The army’s website names King Charles as attending the main ceremony – also known as the Birthday Parade, as it marks the sovereign’s official anniversary.

The princess has been spotted being driven close to her home in Windsor amid speculation about her health. An image circulating online showed the princess, wearing sunglasses, sitting in the front seat of a car being driven by her mother, Carole Middleton.

While the army’s notice suggests Catherine is expected to return to public engagements in June, only Kensington Palace – her official office – can announce her attendance at a royal event. Confirmation is not expected until nearer the time.

She left hospital on 29 January and is recuperating at her Adelaide Cottage home close to Windsor Castle.

Upon her discharge, a Kensington Palace spokesperson said: “She is making good progress. The prince and princess wish to say a huge thank you to the entire team at the London Clinic, especially the dedicated nursing staff, for the care they have provided. The Wales family continues to be grateful for the well wishes they have received from around the world.” It was understood then that her return to official duties would depend on medical advice nearer the time.

The king, who is receiving treatment for cancer, has also postponed all public-facing duties. But he is continuing with behind-the-scenes work on his red boxes of state papers and some in-person meetings.

Charles was pictured on Tuesday during a pre-budget audience with the chancellor, Jeremy Hunt, at Buckingham Palace, before the politician’s major financial statement on Wednesday.