Princess Anne is still continuing with her recovery following a horse-related incident at her home last month.
On Tuesday evening, the Princess Royal was represented by Vice Admiral Sir Tim Laurence at the annual awards dinner for the Royal Academy of Engineering, which was held at The Peninsula London.
Sir Tim, 69, joined news presenter and awards host Krishnan Guru-Murthy on stage where winners were announced.
Princess Anne, 73, recently left the Southmead Hospital in Bristol following a five-day precautionary stay after being injured at her home estate, Gatcombe Park.
HELLO! understands that Anne was out walking within her estate when the incident occurred, resulting in the Princess Royal sustaining minor injuries to her head and a concussion.
While the exact cause of her injuries has not been confirmed, it's understood that her medical team say that her head injuries are consistent with a potential impact from a horse's head or legs.
During her hospital stay, Anne received visits from her husband, Vice Admiral Tim Laurence, and her daughter Zara.
The Princess Royal's two adult children with her first husband, Captain Mark Phillips, have been spotted out and about in recent days.
Zara Tindall, 43, took part in the Aston Le Walls International while Peter Phillips, 46, was seen at the British Grand Prix at the Silverstone Circuit over the weekend.
Since her departure from hospital, Princess Anne has been recuperating at Gatcombe Park, and will return to public duty when her doctors recommend it is safe and comfortable to do so.
Princess Anne's lifelong love of horses
Princess Anne had a successful equestrian riding career in her younger years, becoming the first member of the British royal family to compete in the Olympics, taking part in the 1976 Games in Montreal.
She also won a gold medal in 1971 and two silver medals in 1975 at the European Eventing Championships.
Following in her mother's footsteps, Zara expressed an interest in riding from an early age. She went on to win the Eventing World Championship in Aachen in 2006 and also clinched a silver medal at the London 2012 Olympics as part of Team GB's eventing team.