The veteran musician is a longtime animal rights activist, and he has backed a drive by members of People for the Ethical Treatment of Animals (PETA) which aims to block a proposal by the Russian Federal Space Agency to send four macaques on a mission to Mars in 2017.
A message posted alongside the petition on Peta.org.uk, reads, "The four macaque monkeys that Russia plans to send to Mars in 2017 face years of tests in laboratories - likely followed by a terrifying death in space... There's no reason to repeat the dark days of early space exploration, in which dogs and primates died in horrific ways, all alone in a tiny spacecraft hurtling through space...
"Please sign our petition urging the Russian Federal Space Agency to stop this ill-advised mission and send the monkeys to a sanctuary instead."
Brian has backed the campaign and urged fans to join the fight to save the monkeys.
"I'd like to do something about this. God knows what they have suffered already. Let's sign... Bri," he tweets.