Justin Bieber revealed an 'X' tattoo on Monday night in London. This symbol is the latest addition to his growing collection of tattoos. The tattoo was revealed after the drummer from The Black Keys appeared to mock Bieber on Twitter, prompting strong reactions from 'Beliebers'. 

Although the tattoo may seem mysterious, it is the Greek letter 'Chi', which means 'Christ'.

Bieber, a public Christian, has many other religious tattoos that include a pair of praying hands on his left calf and an image of Jesus on his right, according to The Daily Mail. 

Bieber's new 'X' tattoo is located below the image of an owl, which the singer had inked last year.

Fans on Twitter seemed to like the new ink.  One user commented, "I love how all of @justinbieber's tattoo's has a special meaning. Its amazing :D ♡"

Another said,  "Is that another tattoo I see @justinbieber ;;)"

Bieber revealed the design as he spent the night out in London.

Bieber was wearing baggy jeans, a striped T-Shirt and light denim shirt, with sneakers and shades, as he and his friends spent the night at the Cirque du Soir nightclub.

The group was later seen eating at McDonalds on 'The Strand' before heading back to their hotel.

Bieber is on his UK tour and has just returned to the capitol from Manchester, where he and his entourage reportedly spent £500 on room service in one of the city's premier hotels.

Bieber's X is the latest in a string of tattoos the pop star has revealed recently.

On Twitter, the singer recently posted an image of his leg with a ring of roses underneath his tattoo of praying hands.

Bieber also has a crown on the left side of his chest and the Japanese Kanji symbol for music on his right arm. He received his first tattoo at age 16, when he got the image of a bird on his hip.

He quickly followed it up with the Hebrew word for 'Jesus' on his ribcage. His father got a matching tattoo at the same time during a visit to Israel.

The news of Bieber's new tattoo follows the recent Twitter battle between Bieber fans and Patrick Carney, drummer of The Black Keys.

Carney changed his Twitter profile picture to one of Justin Bieber, and suggested that the pop star didn't deserve any Grammy nominations for his music, according to Christian Post. 

Bieber hasn't responded to Carney's actions of the reactions of his fans in this regard.