The memorial is one of three engagements planned for the Queen next month, following a lengthy period of "light duties" due to ill health late last year.
She will also host a Diplomatic Reception at Windsor Castle on March 2 and make an appearance at Westminster Abbey on March 14 for the Commonwealth Service.
The source said, "The Queen is adamant that she does not want to become a 'digital monarch', who the public only see sitting in an armchair taking video calls.
"She will continue to use her walking stick as a comfort when needed and listen to medical advice."
The service will take place less than three weeks after Andrew sits for a deposition as part of the civil sexual assault case brought against him by Virginia Giuffre, who is suing him in the US.
The 61-year-old prince will be interviewed under oath at a neutral location in London on March 10.
Giuffre - who was formerly known as Virginia Roberts - has accused convicted sex offender Jeffrey Epstein - who committed suicide in August 2019 - and his one-time girlfriend Ghislaine Maxwell of arranging and forcing her into having sex with Andrew in 2001.
The prince has denied all of the allegations and his lawyers have confirmed he's ready to fight the case in court.
Prince Andrew - who is not facing any legal action in the UK - previously requested a trial by jury.