Prince Harry has been accused of breaking military rules for wearing a beard during the Cenotaph in London for the Remembrance Sunday service, even though he's no longer an active member of the armed forces.

UK Press via Getty Images

"Prince Harry is letting us all down," a member of the Army told MailOnline. "There's no place for beards in the Queen's cavalry. He should have shaved it off for such an important day."

Others in the royal family who attended the service -- Prince William and Prince Andrew -- were clean shaven while paying their respects.

HANDOUT/EPA-EFE/REX/Shutterstock

The red-headed royal donned a military outfit for the service, despite having left the Army in 2015. But, his royal duties require him to wear a military outfit on certain occasions. Technically, since he's not in the military, he doesn't have to abide by the military requirements. However, he would normally be expected to live by the military rule when in uniform.

The British Army rules does not allow beards, except in a few rare circumstances. The MailOnline reports that Harry's great-great-grandfather, King George V, sported a beard, as well, so there is precedence for facial hair.

Samir Hussein/WireImage

A military spokesman said Prince Harry does not have to comply with regulations since he's not serving anymore.