Their hit sitcom comes to an end Thursday night after 12 seasons.

And with just a day to go, the cast of The Big Bang Theory greeted excited fans as they arrived for the CBS Upfront presentation Wednesday in New York.

Kaley Cuoco, Jim Parsons, Johnny Galecki and Mayam Bialik spent time signing autographs and posing for selfies outside Carnegie Hall ahead of the event.

And while they will almost certainly go on to other things, the stars know that whatever comes next will be a big transition.

'I’m going to owe all of my career to this show. No matter what I do after this,' Cuoco recently told EW.com.

'This is what made us who we are. We were here for 12 years. This is a big part of our career,' the actress, 33, added.

Galecki, 44, agreed, saying: 'It will never be fully eclipsed. We will always be associated with one another. It’s such an incredibly unique experience.'

And with just a day to go, the cast of The Big Bang Theory greeted excited fans as they arrived for the CBS Upfront presentation Wednesday in New York.

Kaley Cuoco, Jim Parsons, Johnny Galecki and Mayam Bialik spent time signing autographs and posing for selfies outside Carnegie Hall ahead of the event.

And while they will almost certainly go on to other things, the stars know that whatever comes next will be a big transition.

'I’m going to owe all of my career to this show. No matter what I do after this,' Cuoco recently told EW.com.

'This is what made us who we are. We were here for 12 years. This is a big part of our career,' the actress, 33, added.

Galecki, 44, agreed, saying: 'It will never be fully eclipsed. We will always be associated with one another. It’s such an incredibly unique experience.'