Buzz Aldrin appeared to criticize Neil Armstrong biopic First Man for leaving out the planting of the American flag on the Moon.
The 88-year-old, who was the second man to set foot on the Moon, on Sunday tweeted a picture of the flag planted after the landing in 1969.
He captioned the photo: 'Proud to be an American.' Aldrin also re-tweeted a photo of him saluting next to the same picture.
It is an apparent dig at Oscar-winning director Damian Chazelle's controversial decision not to include the planting of the flag at the end of his critically acclaimed movie.
The film is not kind in its portrayal of Aldrin, with Corey Stoll's performance painting him as an 'obnoxious loudmouth' and 'so blunt about his ambition that no one can stand him.'
Other reviews described Stoll's Aldrin as a 'swaggering hothead' who is 'cynical, mouthy and insensitive' while one reviewer said his appearances were so scarce that
he was all but left out of the film.