Police have arrested two men in Thailand for possessing protected slow loris monkeys after spotting a holiday photo posted on Instagram by world-famous pop star Rihanna.

The Umbrella singer was taking a break from her Diamonds world tour in Phuket last week when she snapped the photo, which shows her holding the endangered primate.

"Phuket authorities were alerted to the picture, and … police [have] arrested the two individuals who brought out the loris as a photo opportunity for tourists," Weera Kerdsirimongkon, a Phuket district chief police officer, told Associated Press.

A 20-year-old man and a 16-year-old boy have been arrested and police have confiscated two slow loris monkeys, which will be returned to a national park in Phang Nga.

The accused will wait to see whether they will face charges of animal peddling, which could lead to a maximum prison sentence of four years and a fine of up to US $1,300.

Although the photo that Rihanna snapped with the rare animal outraged many, others have seen it as a good opportunity to promote conservation efforts.

“The center of the story is that these people were arrested because this is a protected animal,” Rachel Munds, an anthropologist at the University of Missouri-Columbia, told National Geographic.

“That emphasizes that these animals aren’t something to be photographed with.”

The loris monkey is an endangered species in Asia and is becoming increasingly rare. Although many of the animals are bought as pets on the black market, they make less than ideal companions due to their nocturnal habits and toxic bite.