The Big Bang Theory is coming to an end, and the show's spinoff, Young Sheldon is paying homage to the parent series for its upcoming finale.

TV Line is reporting that Leonard, Penny, Amy, Raj, Howard, and Bernadette will be appearing on Young Sheldon Season 2 Episode 22 -- the season finale.

But that's not to say the same actors who play them on Young Sheldon will be stopping by. The spinoff is set several years before the beginning of The Big Bang Theory.

It wouldn't be possible for the same actors to play them unless the spinoff was going ot feature a flash-forward.

Instead, there will be new actors taking on the much-younger iterations of the characters made famous by TBBT.

It's also unclear what kind of plot brings all of these people together. If you watch Young Sheldon online, you know that neither of the above characters are part of his childhood.

Alas, this is a great way to honor the series that started it all. It's exciting that even after The Big Bang Theory's series finale, fans can tune into an episode of the spinoff with a big payoff for them.

It was announced in August that The Big Bang Theory would be wrapping up after its 12th season.

In a joint statement, Warner Bros. Television, CBS and Chuck Lorre Productions said, “We are forever grateful to our fans for their support of The Big Bang Theory during the past twelve seasons."

"We, along with the cast, writers and crew, are extremely appreciative of the show’s success and aim to deliver a final season, and series finale, that will bring The Big Bang Theory to an epic creative close.”

As for Young Sheldon, that has been renewed for seasons 3 and 4, so there's no end in sight for the spinoff.