The reception celebrated 100 years since women were recruited for service in the Army and Navy in a non-nursing capacity for the first time.
The Queen is the Patron of the Women's Royal Auxiliary Corps (WRAC) Association, which incorporates the Women's Auxiliary Army Corps (WAAC) and the Auxiliary Territorial Service (ATS).
The WAAC later became the Queen Mary's Army Auxiliary Corps, when The Queen's Grandmother, Queen Mary, became its Patron.
The Princess Royal has a long connection with the Women's Royal Naval Service (WRNS); she is Patron of the WRNS Benevolent Trust, the Association of Wrens and the WRNS100 Project. HRH is also the Admiral and Chief Commandant for Women in the Royal Navy.
At the reception, The Queen and The Princess Royal met many members of the Association's and heard about their experiences.
The Queen joined the ATS 1945, aged 18, and became the first female member of The Royal Family to join the Armed Services as a full-time active member.
The WRNS and WRAC also put on a display that charted the progression of women serving in the Army from 1917 to the present day.
The WAAC and WRNS were originally established in 1917 in reaction to the deteriorating man power situation, as so many men had been killed or injured. By the end of WWI, the WRNS had approximately 5,000 ratings and nearly 450 officers. Jobs included sail-making, driving, signalling & coding.
During 2017 the WRNS100 Project is underway, which will involve 116 national and regional events are planned, culminating in a Service at Portsmouth Cathedral in November.