Marvel has defended its decision to cast Tilda Swinton as the Ancient One in the upcoming Benedict Cumberbatch-starring "Doctor Strange" as mounting criticism for the casting decision has reached social media.

Accused of whitewashing, the studio responsible for the Marvel Cinematic Universe claims that the decision was made to "appease" Chinese audiences, especially since China has become the world's second biggest film market after the North American box office, Variety reported.

The Ancient One was a character in the "Doctor Strange" comic series who was born in Kamar-Taj, which implies his ethnicity is either Tibetan or Nepalese. The Ancient One eventually meets Doctor Strange and becomes his mentor.

In a statement sent to Mashable, the Disney-owned company insisted on its "strong record" of casting actors and actresses from diverse racial and socioeconomic backgrounds.

"The Ancient One is a title that is not exclusively held by any one character, but rather a moniker passed down through time, and in this particular film the embodiment is Celtic," the statement reads.

Marvel also said that it is "proud" to have Swinton be part of the fantasy film's cast.

According to the Hollywood Reporter, an interview of one of the screenwriters involved in the motion picture, C. Robert Cargill, started the online firestorm after he suggested that casting a Tibetan in the role might backfire as it might not sit well with the Chinese government and audiences. He also said that whoever is going to be cast as the Ancient One would be controversial either way because the character is a "racist stereotype."

For her part, the "We Need to Talk about Kevin" actress explained that she was not chosen to play an Asian character.

Scarlett Johansson is also facing online backlash for being cast as the lead of the American live action remake of the popular Japanese manga "Ghost in the Shell."