Family Guy” is prepping for a very special episode — one that will not only break format to be presented with limited commercial interruptions, but also will center the youngest Griffin family member, Stewie, confronting some insecurities.

In the episode titled “Send In Stewie, Please,” which airs Mar. 18, Stewie finds himself in the office of his school’s psychologist, Dr. Cecil Pritchfield (voiced by guest star Sir Ian McKellen), where he’s forced to confront his own behavior and ends up addressing some long-speculated fan theories.

With the show in the midst of its 15th season, executive producer Rich Appel tells Variety that it’s the perfect time to take an ambitious creative leap.

“The very fact that this show has been on the air for as long as it’s been makes this episode a lot more fun and potentially rich,” says Appel.

“Whenever we get a chance to do something different, I think we’re all very excited about that,” agrees executive producer Alec Sulkin. “We were not afraid to keep them in a room together for the entire episode and not have it go anywhere else. I think we just embraced that and had a lot of fun with it.”

Appel says the creative team recognized that Stewie, who’s become “an at least memorable and possibly iconic character” was ripe for a therapeutic setting where he might at last be confronted with a staple question of psychoanalysis: what part of his character is based on the world around him, and what part is self-invention?

“Of all the characters on any animated show,” says Appel. “Stewie seems like he potentially could both benefit from and be scared of therapy more than any other.”

For these moments, the producers turned to veteran “Family Guy” scribe Gary Janetti, who’s been with the show and specialized in crafting Stewie scenarios since the very beginning.

“I was kind of given a lot of flexibility to find it as I wrote it,” says Janetti. “We talked briefly about what it would be, but in a weird way, as I was writing it, it kind of revealed itself to me.”

Janetti says his process was to allow himself to think like the character and “just let it just run and run and run.”

“I was hopefully trying to find the story within that, which happened,” Janetti notes.

Along with unloading a long-hidden facet of Stewie’s psyche, Janetti also wanted to address his more diabolical inclinations.

“Stewie has done a lot of horrible things in the course of the series, and has he ever thought about that? What are the ramifications of the things that he’s done? The accountability, as it were,” he points out.

Janetti also made the decision to shatter sitcom convention by having Stewie deliver a more epic, more brutally incisive and potentially devastating monologue than anything the Griffin’s baby has ever uttered before.

“I’ve always wanted to write one that went on and on, but there was never an appropriate place for it until this episode,” says Janetti. “That one was just a bit of stream of consciousness. I wanted to see if I could bring it to its natural conclusion with his convoluted logic. Also, we know that Stewie can take down people and what a keen observationalist he is, and he can spot somebody’s flaws instantly at a glance – it’s almost like his Sherlock Holmes’ ability – and it was taking that to the fullest extent.”

Appel says that having “Family Guy” creator Seth MacFarlane on hand to give voice to Stewie gave them confidence that they could pull off many of the episode’s riskier elements, this monologue included.

“It’s a very ironically three-dimensional performance, that not every character in our show who we really like could withstand that,” Appel explains. “Not every character’s as rich or as complicated as Stewie, and Seth’s performance adds to that layer, too.”

Equally crucial was the casting of McKellen as Dr. Pritchfield, which came to pass because Janetti had co-created the UK series “Vicious,” which starred the esteemed actor.

“I said, ‘Well, if we’re going to have somebody go toe to toe with Stewie it could only work if you had a really formidable adversary for him, and there’s no better person to go up against Stewie than Ian McKellen,” says Janetti, who tailored the role for his friend. “He was very enthusiastic, and he loves Stewie.”

Ironically, despite all of its game-changing elements, “Send In Stewie, Please” was also cleverly and deliberately crafted to stand apart, allowing the series to settle back into its conventions in its wake.

“If you miss this episode, that’s fine, it won’t affect your watching of the show,” says Janetti. “We get to learn more about him in this episode. It deepens our understanding of him going further, but I don’t foresee it’s something that will be acknowledged again — nor do I think it should.”

The fact that the network was behind the episode not only creatively but from the business side and is “generously” presenting it with limited breaks was a big deal for the producers, as well. They now hope that this episode may pave the way for future ones of its nature.

“The show is always looking to find new ways to tell stories and to take risks, and it’s always been like that since the first day I was there almost 20 years ago,” says Janetti. “To spend an intense amount of time with Brian would be something that I would very much enjoy doing.”