The Queen is returning to public duties after falling ill with a chest infection but will miss a late night out at the star-studded Gladiator II premiere to aid her recovery, a royal source said.

Camilla’s appearances this week have also been shortened to prevent any setback after she contracted the nasty seasonal bug following her long-haul tour to Australia and Samoa.

She is attending a Booker Prize reception with shortlisted authors at Clarence House on Tuesday, her first engagement since she became unwell.

But she will be there for a shorter period than planned, joining guests only for a discussion and a group photograph.

Camilla will still join the King at a special palace reception on Wednesday celebrating the TV and film industry, but she is not expected to stay for the entirety of the engagement.

The Queen has also pulled out of the royal premiere of Gladiator II on Wednesday evening in London’s Leicester Square where she was due to meet Paul Mescal, Denzel Washington, Connie Nielsen and Pedro Pascal, and director Sir Ridley Scott.

The changes to her diary are understood to have been made to protect and prioritise her continued recovery, with royal doctors keen to prevent any setback.

Camilla was forced to miss gathering with the King, the Princess of Wales and the rest of the royal family at the annual Remembrance Sunday at the Cenotaph, and the Festival of Remembrance at the Royal Albert Hall the evening before.

Tuesday will be the first time she has been seen in public since the end of her trip to Australia and Samoa two and a half weeks ago.

Thursday is the King’s 76th birthday when Charles is marking the day by opening the first two Coronation Food Hubs – one in person and one virtually.

Camilla, 77, had hoped to join him, but the visit will remain a solo one.

Meanwhile, a documentary focusing on the Queen’s work raising awareness of domestic violence aired on Monday evening, with Camilla watching the final edit for the first time at her Wiltshire home Raymill.

She is said to have been delighted by the end result and the impact it appears to have had.

The Queen was followed over the course of a year for the ITV1 and ITVX programme Her Majesty The Queen: Behind Closed Doors, and in it she vowed to “keep trying” to end domestic violence, describing it as a “heinous crime”.