Rajesh Ramayan "Raj" Koothrappali, Ph.D.[1] is a fictional character and one of the main protagonists on the 2007-2019 CBS television series The Big Bang Theory, portrayed by British-Indian actor Kunal Nayyar.

He is one of four main male characters in the show, alongside Sheldon Cooper, Leonard Hofstadter and Howard Wolowitz to appear in every episode of The Big Bang Theory.

Raj is normally seen wearing a layered combination of a printed shirt and sweater vest under a track top-style windbreaker with khakis or cargo pants and skate shoes.

[3] Raj wore a red cap in the pilot episode, but has not worn any headgear on a regular basis for the rest of the series run.

[4] Another recurring joke is his metrosexuality, which manifests itself in his appreciation for media generally associated with female patrons, such as the novel Eat, Pray, Love, the TV series Sex and the City and films featuring Sandra Bullock.

This has led those close to him to believe that he is somewhat feminine (as in "The Closure Alternative"), and others to mistakenly conclude that he is homosexual (a theory his sister mentioned in "The Herb Garden Germination" that had been held by members of their family), which he typically denies (even asserting his metrosexuality in "The Transporter Malfunction"), but which Howard often teases him over.

In the show, one of Raj's biggest personality quirks is his tendency to speak or act inappropriately, often landing him in trouble or leading to an angry reaction from whomever he has upset.

On one occasion, just as Leonard and Penny are about to have intercourse in their hotel room, Raj enters and proceeds to climb into Sheldon's recently vacated bed, completely oblivious of what he has interrupted.

Until the season six finale, Raj's principal characteristic is his inability to speak to or around unrelated women, a form of a medical condition known as selective mutism.

Later, in "The Bat Jar Conjecture", Raj accidentally utters the words "good story", much to the surprise of his friends, but he immediately realizes Penny is there and covers his mouth with both hands.

In "The Grasshopper Experiment", Penny (who is practicing mixing cocktails in order to obtain a bartending shift) inadvertently discovers that Raj's mutism could be suppressed by consuming alcohol: even a tiny amount (such as a bite of rum cake in "The Apology Insufficiency") enables him to have prolonged conversations with women; however, this also tends to make him loud and obnoxious.

When Sheldon's attractive sister Missy visits, Raj takes medicine that enables him to speak to her, but it results in involuntary repetitive hand motions.

Raj's cousin Sanjay (or, as he says his friends know him, "Dave from AT&T Customer Service") works in a call centre and is mentioned in a number of episodes.

In the Season 4 finale, Raj had to move temporarily into Sheldon's apartment after overhearing Leonard using Star Trek references as sexual metaphors to his sister.

[17] For his discovery of a planetary object beyond the Kuiper belt, 2008 NQ17, which he named "Planet Bollywood", Raj was included in People magazine's "30 (Visionaries) Under 30 (Years of Age) to Watch", received a larger office, and became a celebrity of sorts, drawing the envy of his friends.

[18] In the show, after six months of failed research on the composition of trans-Neptunian objects, Raj feared being deported back to India (at which point, he describes spending his time at work as "mostly checking e-mail, updating his Facebook status, and messing up Wikipedia entries").

To stay in the country, he sought out a research position in stellar evolution with Professor Laughlin, failing as the research team included an attractive woman, and Raj, who became drunk so he could talk to her, made an inappropriate comment; in retaliation, Raj filed a complaint against Laughlin, claiming the British professor discriminated against him.

[24] This antagonizes Howard when he learns of it, although Raj attempted to reassure him that it was no longer an issue, believing that he and Penny were together and in love after a drunken one-night stand.

In the season 4 finale, Penny and Raj become intoxicated and, despite agreeing to remain good friends, end up in bed together, giving the impression that they had had intercourse.

The next morning, both agree to pretend it never happened, but they are caught by Leonard, Sheldon, and Howard as they try to leave,[26] causing Penny to consider moving back to Nebraska.

Happy with his new companion, a female Yorkshire Terrier he names Cinnamon, Raj proceeds to see if the pup fits in his man-purse.

In the season six episode "The Tangible Affection Proof", Raj and Stuart put together a party at the store for lonely single people on Valentine's Day.

In "The Monster Isolation", Lucy flees during their coffee date, sending Raj into depression and self-isolation in his apartment wearing nothing but briefs and Uggs.

In the following episode, "The Contractual Obligation Implementation", he takes Lucy out for a first date to a library where they text message each other instead of speaking, in light of her social anxiety and his selective mutism.

Raj apologizes for his behavior and asks Lucy to come to Leonard's goodbye party before his departure for the North Sea on Professor Stephen Hawking's expedition.

Penny suggests that this lament is attributed to alcohol, but Raj says he that he has not had a drink since the night before: they learn that he is finally cured of his selective mutism.

Eventually, he begins dating Emily Sweeney (Laura Spencer), an attractive but rather sinister young dermatologist he met on the Internet.

However, near the end of the season, Anu accepts a job offer in London and asks Raj if he is prepared to move to England to live with her.

Raj did not appear in the original, unaired series pilot, which only featured Leonard, Sheldon, and a different version of the Penny character, called Katie.

When scenes called for Raj to drink grasshoppers, the substitute was a concoction of water, cream and a heavy amount of green food coloring.