Can you become a Sir if you are deceased?

No sorry it can't happen, but he should have been knighted before he died.

RIP Freddie. He is a “Sir” in my book. Who needs royalty to tell us how great he was? An amazing voice!

No. Nor can you have your knighthood removed.

No, titles are not awarded to dead people, how could they be?

They were going to do that with George Harrison and then decided it's silly, because it is.

No. The rule is that after your death you cannot be given an honour or a title, nor can one you received in life be stripped from you.

The logic of this is that values change over time, and the people who are admired in one era are despised in another. If people could be given or be stripped of titles post mortem, there would be no end to it; history would turn into a non-stop game of Pin the Tail on the Donkey as people we used to admire were de-titled and people who were not appreciated in their lifetime were elevated - only for everything to be reversed a generation later.

Hi Hi. No, posthumous knighthoods are never given and when the recipient of a Knighthood dies, the honour dies with him.

No; the knighthood is not granted posthumously as it is a life honor.

No. It's an honour given only to living people.

No you can't so it will never happen.