The Big Bang Theory has been wildly successful for a number of years now, but last August we found out that it was coming to an end. By the time it wraps up, their legacy as the longest-running multi-camera comedy in history will include twelve seasons and over 250 episodes. Not too shabby!

Today's the day it all comes to an end, with a one-hour double episode airing on CBS this evening - airing its 278th and 279th episode as the cast bid farewell to their adoring fans.

Watch the preview for the finale here:

The first of the double bill will be 'The Change Constant', in which Sheldon and his wife Amy "await big news" about their Nobel Prize contending project.

Meanwhile, in the following (and final) episode, 'The Stockholm Syndrome' we'll be seeing: "Bernadette and Wolowitz leave their kids for the first time; Penny and Leonard try to keep a secret; Sheldon and Amy stick together; Koothrappali makes a new friend," while "the gang travels together into an uncharted future".

Kaley Cuoco, who plays Penny on the show, took to her Instagram account following the news back in 2018, where she shared a heartfelt goodbye to the fans:

"This ride has been a dream come true and as life changing as it gets. No matter when it was going to end, my heart would have always been broken in two. Drowning in tears, we promise to bring you the best season yet.

"To the fans, our crew, families, Chuck Lorre, Warner Brothers, CBS, and everyone who has supported us for so many years, thank you. We are goin out with a bang"

Things got even more emotional for the actress and her fellow castmates late last month, as Cuoco shared on Instagram. She posted a photo taken after the last-ever Big Bang Theory table read, showing herself barely able to hold it together.

Having gone through a similar process at the end of Friends, actress Courtney Cox commented to show her love, writing: "awww I remember that feeling...and you guys have been together even longer ?♥️??".

Johnny Galecki, who plays Leonard, also got really emotional over the table read it seems. He too shared a photo of him struggling to keep his feelings in check.

"This morning was not an easy one. The final table reading for @bigbangtheory_cbsSo very sad. So very grateful," he wrote.

On her Instagram page, Melissa Rauch also weighed in on about the close of the show, and how she felt about those last moments spent on set with the other members of the cast. She wrote:

"Just because I haven’t flooded my face with enough tears during/after today’s final @bigbangtheory_cbs table read...here’s a pic of our pre-show huddle last night. I was always picked last for every team as a kid, so getting to be a part of a huddle ~ let alone this particular huddle has been extra special. I‘ll forever cherish these moments with my TBBT brothers and sisters. ?"

The two-part series finale airs tonight (May 16) at 9 pm EST.

The Big Bang Theory has been wildly successful for a number of years now, but last August we found out that it was coming to an end. By the time it wraps up, their legacy as the longest-running multi-camera comedy in history will include twelve seasons and over 250 episodes. Not too shabby!

Today's the day it all comes to an end, with a one-hour double episode airing on CBS this evening - airing its 278th and 279th episode as the cast bid farewell to their adoring fans.

Watch the preview for the finale here:

The first of the double bill will be 'The Change Constant', in which Sheldon and his wife Amy "await big news" about their Nobel Prize contending project.

Meanwhile, in the following (and final) episode, 'The Stockholm Syndrome' we'll be seeing: "Bernadette and Wolowitz leave their kids for the first time; Penny and Leonard try to keep a secret; Sheldon and Amy stick together; Koothrappali makes a new friend," while "the gang travels together into an uncharted future".

Kaley Cuoco, who plays Penny on the show, took to her Instagram account following the news back in 2018, where she shared a heartfelt goodbye to the fans:

"This ride has been a dream come true and as life changing as it gets. No matter when it was going to end, my heart would have always been broken in two. Drowning in tears, we promise to bring you the best season yet.

"To the fans, our crew, families, Chuck Lorre, Warner Brothers, CBS, and everyone who has supported us for so many years, thank you. We are goin out with a bang"

Things got even more emotional for the actress and her fellow castmates late last month, as Cuoco shared on Instagram. She posted a photo taken after the last-ever Big Bang Theory table read, showing herself barely able to hold it together.

Having gone through a similar process at the end of Friends, actress Courtney Cox commented to show her love, writing: "awww I remember that feeling...and you guys have been together even longer ?♥️??".

Johnny Galecki, who plays Leonard, also got really emotional over the table read it seems. He too shared a photo of him struggling to keep his feelings in check.

"This morning was not an easy one. The final table reading for @bigbangtheory_cbsSo very sad. So very grateful," he wrote.

On her Instagram page, Melissa Rauch also weighed in on about the close of the show, and how she felt about those last moments spent on set with the other members of the cast. She wrote:

"Just because I haven’t flooded my face with enough tears during/after today’s final @bigbangtheory_cbs table read...here’s a pic of our pre-show huddle last night. I was always picked last for every team as a kid, so getting to be a part of a huddle ~ let alone this particular huddle has been extra special. I‘ll forever cherish these moments with my TBBT brothers and sisters. ?"

The two-part series finale airs tonight (May 16) at 9 pm EST.