The late Queen wrote about the difficulties of grieving in public in a poignant letter written to the former Archbishop of York after the death of her husband, Prince Philip.
Crossbench peer Lord Sentamu said that the Queen spoke in her letter of her deep love for her husband, the Duke of Edinburgh, who passed away on 9 April 2021.
"The Queen wrote me a most wonderful letter four weeks after the burial of Prince Philip, thanking me for the flowers, the prayers and then ended by saying 'when you are grieving someone you deeply love, it isn't easy when you have to do it in public'," he said.
Lord Sentamu was speaking to the BBC's Laura Kuenssberg ahead of the Queen's state funeral on Monday.
He said his thoughts would be with King Charles III and the royal family who, like the Queen after the death of Prince Philip, are now "grieving publicly".
He added that the funeral would be a "glorious" because the Queen did not want a long and boring service.
"So what you're going to expect is the best of funeral services, the prayer book service, the words which were an inspiration to Shakespeare," he said.
"So you're going to hear this wonderful English at its best, also you're going to hear angelic voices of the choir of the Abbey plus the Chapels Royal, you really hear voices that are singing to the glory of God.
"The Queen does not and did not want what you call long, boring services, you're not going to find boredom, but you're going to be lifted to glory as you hear the service."
He added: "The hearts and people's cockles will be warmed and at the same time, there will be a moment of saying this is a funeral service that is glorious in its setting."