“That’s one small step for man, one giant leap for mankind.” The famous quote by astronaut Neil Armstrong after taking the first steps on the moon is one of the most well-known in recent history but it also has a story of its own.

It has long been disputed if Armstrong had intended to include an “a” in the quote — “That’s one small step for a man, one giant leap for mankind.” But a documentary called “Neil Armstrong — First Man on the Moon” broadcast on BBC Two on Sunday might have closed the discussion, revealing the backstory of the late Armstrong’s line.

Neil Armstrongs Brother Said the Astronaut Thought Out Famous Line Before Landing on the Moon

This July 20, 1969 file photo provided by NASA shows Neil Armstrong. Armstrong died in 2012. (Photo: AP/NASA)

The Daily Telegraph reported that Armstrong’s words were thought out well in advance and an “a” was in fact meant to be included, something Armstrong always maintained. It was Armstrong’s brother Dean who confirmed this during the show, saying he was asked to review the line while the pair were playing the board game Risk.

Here’s more from the Telegraph of Dean Armstrong’s interview:

He said: “Before he went to the Cape, he invited me down to spend a little time with him. He said ‘why don’t you and I, once the boys go to bed, why don’t we play a game of Risk’.

“I said I’d enjoy that. We started playing Risk and then he slipped me a piece of paper and said ‘read that’. I did.

“On that piece of paper there was ‘That’s one small step for man, one giant leap for mankind’. He says ‘what do you think about that?’ I said ‘fabulous’. He said ‘I thought you might like that, but I wanted you to read it’.”

He then added, [correcting his brother]: “It was ‘that is one small step for A man’.”

Neil Armstrongs Brother Said the Astronaut Thought Out Famous Line Before Landing on the Moon

In this 1969 file photo, astronauts Edwin E. Aldrin and Neil Armstrong rehearse tasks they will perform on the moon after landing in July 1969 during the Apollo 11 mission. (Photo: AP/NASA, File)

This perhaps closes the argument over the missing word.

Armstrong died in August this year at age 82.

Listen to Armstrong speaking on the moon in this video:

Related:

(H/T: Gizmodo)