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It’s bound to be an emotional night for the cast of The Big Bang Theory.

Jim Parsons, Johnny Galecki, Kaley Cuoco, Kunal Nayyar and Melissa Raunch took to Instagram ahead of Tuesday’s final taping to say goodbye to their characters, the set and their castmates.

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Parsons, who plays Sheldon Cooper on the hit sitcom, shared a photo of apartment 4A, Cooper’s residence for the majority of the 12 seasons of The Big Bang Theory, writing: “Knock, knock, knock, thank you… Thank you, apartment 4A, for being a home to so many dreams come true, to so many friendships made. And thank YOU, ALL of you – yes, YOU, reading this right NOW!”

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He continued: “As we get ready to tape our final episode tonight, to walk in and out of this apartment door for the last time, it is hard to find the words to articulate what a profound experience this has been. But the words ‘love’ and ‘gratitude’ come to mind… so love and gratitude to all of you. ALL of you. Thank you.”

Galecki, who stars as Leonard, shared a similar photo as his on-screen best friend but opted for a last look at room 4B, the apartment Sheldon moved into after marrying his wife on the show, Amy.

“More feelings than words can express,” he wrote alongside the image.

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Kunal Nayyar (Rajesh Koothrappali) went with a photograph of a cast-hug.

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And Raunch (Bernadette) shared a cast selfie, with the simple word “Forever” as her caption.

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Cuoco shared a look behind-the-scenes, writing, “Final bows tonight.”

Big Bang Theory will wrap their 12th and final season on Tuesday night after being on the air since 2007.

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