Not just as narrators, they will appear onscreen this time.

https://tvline.com/lists/young-sheldon-jim-parsons-mayim-bialik-cast-series-finale/young-sheldon-amy-reunion-1/

Young Sheldon's Jim Parsons Cameo Is Good, But I Won't Be Happy Unless 1 Other TBBT Actor Returns (https://screenrant.com/young-sheldon-finale-jim-parsons-cameo-big-bang-theory-leonard-missing/)

Jim Parsons will appear in the Young Sheldon series finale, but it would mean nothing if he isn't joined by another The Big Bang Theory character.

Not sure if I'm in favor of either of them to be on camera at the wrap up of this show. Kind of takes away from the regular cast who have made the show what it is. Just my take though. Maybe there's a genuine need for them???

Jim Parsons Calls Appearing in the 'Young Sheldon' Finale "Beautiful" and "Sweet" (https://collider.com/young-sheldon-jim-parsons-the-big-bang-theory/)

The 'Spoiler Alert' actor is reuniting with Mayim Bialik for the final episode of the spinoff series and hit sitcom.

Jim Parsons' Young Sheldon Season 7 Update All But Confirms My Fear Over Its TBBT Cameos (https://screenrant.com/young-sheldon-season-7-jfinale-im-parsons-big-bang-theory-cameo-fears/)

Details about Jim Parsons' Young Sheldon appearance almost confirm a disappointing element in the much-anticipated send-off for the Coopers.

Young Sheldon Star Iain Armitage Shares Reaction To Having Jim Parsons & Mayim Bialik On Set (https://screenrant.com/young-sheldon-season-7-ending-jim-parsons-mayim-bialik-cameos-set-response-iain-armitage/)

Young Sheldon star Iain Armitage shares his reaction to having Jim Parsons and Mayim Bialik on set, reprising their roles from The Big Bang Theory.

Iain Armitage Meets Jim Parsons in New 'Young Sheldon' Set Video (https://collider.com/young-sheldon-set-video-jim-parsons-iain-armitage/)

Young and Old Sheldon meet!

Young Sheldon Season 7 Finale Title Reveals Jim Parsons' Role & Ties To TBBT (https://screenrant.com/young-sheldon-season-7-finale-title-jim-parsons-role/)

Ahead of its series-capper, CBS confirms Jim Parsons' role in the upcoming Young Sheldon finale and how it ties to The Big Bang Theory.

Young Sheldon Season 7 Cameo Risks Making Its Big Bang Theory Plot Holes More Obvious (https://screenrant.com/young-sheldon-season-7-cameo-jim-parsons-plot-holes/)

Young Sheldon bringing in The Big Bang Theory's Jim Parsons for its series finale could make the spinoff's countless plot holes more obvious.

How Old Are TBBT’s Sheldon & Amy In The Young Sheldon Finale Flashforward (https://screenrant.com/how-old-big-bang-theory-sheldon-amy-in-young-sheldon-finale/)

Adult Sheldon and Amy properly appear in the Young Sheldon (https://screenrant.com/tag/young-sheldon/) finale, but how exactly are The Big Bang Theory characters in the flashforward?

Where Are Penny And The Rest Of The Big Bang Theory Cast In The Young Sheldon Finale? (https://screenrant.com/where-are-penny-the-big-bang-theory-cast-in-young-sheldon-finale/)

The Young Sheldon finale features a flashforward featuring Sheldon and Amy, making the rest of The Big Bang Theory cast's whereabouts curious.