How the 'classiest' A-list celebrity ended up voicing a sexy octopus on 'The Boys' season 4

• Season four of "The Boys" features the return of the octopus named Ambrosius, voiced by an A-lister.
• Star Chace Crawford told Business Insider that he had "no idea" who would be voicing the sea creature. 
• Showrunner Eric Kripke said he specifically wanted "the most British, Oscar-winningest, classiest actor."

Warning: Major spoilers ahead for season four of "The Boys."

"The Boys" star Chace Crawford never knows what kinds of antics his character, The Deep, will be involved in — but having an octopus lover voiced by Tilda Swinton certainly wasn't on his bingo card for season four.

"I kind of take it as I open the scripts, right?" Crawford told Business Insider in a recent interview ahead of the season four premiere on Thursday. "I had no idea that it was going to be Tilda Swinton."

Last season, The Deep encountered a female octopus named Ambrosius while attending Herogasm. The supe, who can breathe underwater and communicate with sea creatures, ended up taking the octopus home with him and continuing to have sexual relations with her — to the disgust of his wife, Cassandra (Katy Breier).

The season four premiere of "The Boys," released Thursday on Prime Video, reveals that The Deep is now divorced and dealing with allegations from Cassandra's biography, "In 2 Deep: My Journey 2 Freedom."

In an interview, The Deep denies having sexual relations with an octopus, and he later tells Vought employee Ashley Barrett (Colby Minifie) that the sea creature has been "taken care of."

But instead of getting rid of Ambrosius, The Deep stashes her away in a tank in his closet, carrying out a secret relationship with her.

"Once we decided that The Deep and Ambrosius were going to have this intense affair and we were going to be able to hear her, we just were like, we need the most British, Oscar-winningest, classiest actor we can possibly find for that part," showrunner Eric Kripke told BI. "There's four of them in the world, and Tilda Swinton is one of them."

"The Boys" team didn't have a personal connection to the Academy Award winner but reached out to her reps, and she was game to voice the eight-armed sea creature.

"She came into the booth for one long session, and I was there, and it was really a pinch-me moment watching this world-class, highest caliber actress say the most ridiculous shit as Ambrosius," Kripke said.

After four seasons of playing The Deep, Crawford said that he's still impressed by the creativity and attention to detail the show's VFX team puts into crafting its creatures.

"I'm always doing little things like in the air, pushing off tentacles and stuff, and then to see them add that in and make it come to life…" Crawford said as Kripke chimed in to point out that Ambrosius also has a tiny figurine of The Deep in her tank to keep her entertained.

"The guys are brilliant. And even the Timothy thing, I had no idea what that was going to be and they make it look so good," Crawford said, referencing The Deep's other octopus companion from season three. "So, it's always fun for me to see what's next."

The first three episodes of season four of "The Boys" are now streaming on Prime Video, followed by a new episode each week, ending with the season finale on July 18.