Pop superstar Rihanna raised eyebrows on social media after she posted some photoshopped pictures of Queen Elizabeth II.

Axar.az reports citing local media.

The Barbadian singer and songwriter, 29, celebrated the monarch's 91st birthday by posting on her Instagram account four photos of the queen with the monarch's face superimposed onto snaps of Rihanna's in fashionable outfits.

One of the posts showed that the queen head, including her stylish green hat, was photoshopped onto a paparazzi photo of Rihanna walking down the street in a green fur coat and over-the-knee boots. "Be humble," she wrote below the image.

Although some of the singer's 52-million followers found the photos funny, others vented their outrage in the comments section, accusing her of being "disrespectful."

"It's rude you know. This is not funny. She's someone's grandma. Imagine if its yours," a user wrote. "This is disrespectful and stupid," another user commented, "The queen is 91 and she deserves respect."

Some fans believed that the singer was simply paying tribute to the queen. "It's just a way to say Happy Birthday and I don't think it's that much important," a follower said.

Rihanna has not yet responded to the criticisms so far.