The monarch greeted the High Commissioner of India and the Ambassador of Armenia, who spoke to her via video-link from Buckingham Palace on Tuesday.
Wearing an orange dress, the 95-year-old head of state chatted to the diplomats as they presented their credentials.
Gaitri Issar Kumar, the High Commissioner of India, gave a namaste greeting, while Armenian ambassador Varuzhan Nersesyan bowed to the monarch.
On Monday, the Queen held her first in-person engagement since catching Covid, meeting Canadian Prime Minister Justin Trudeau.
Mr Trudeau said at a Downing Street press conference afterwards that the monarch was “as insightful and perspicacious as ever” tweeting “It’s always wonderful to see Queen Elizabeth II.
“When we met at Windsor Castle, we spoke about a wide range of issues – including global affairs, the situation in Ukraine, and Her Majesty’s lifetime of service to Canada and the Commonwealth.”