Tube ‘Bang’ meets ‘Sheldon’

As The Big Bang Theory rolls into its final season, its writers are looking to tidy up some loose ends, writes Bill Keveney.

WONDERING why Sheldon has never mentioned his boyhood best friend Tam on The Big Bang Theory, even though he’s seen on prequel Young

Sheldon?

Producers promise an answer as adult Tam surfaces on the toprated comedy.

Besides Tam, there’s a good chance Big Bang viewers will meet a grownup Billy Sparks, Sheldon’s childhood bully who seems more like a big, simple boy on Sheldon.

Look for more connections between the sibling shows this season, but don’t expect newlyweds Amy and Sheldon to become parents, despite narrator Sheldon’s reference to his children in last week’s Season 1 Sheldon finale.

‘‘We’ve talked about the arc for where we want to end, but it’s not all officially ingrained. I’m hesitant to talk too much about it now, but right now that’s not part of the plan,’’ says Big Bang executive producer Steve Holland, adding there will be ‘‘no more babies’’. As for the final episode, ‘‘we’ve talked about it. We don’t know the whole thing. We have some ideas we’re really excited about, but nothing set in stone yet.’’

Big Bang writers typically don’t plot too far ahead, so Holland and Steven Molaro, an executive producer of both comedies, say they have time to prepare a satisfying conclusion after it was announced in August that the 12th season would be its last.

‘‘We have time to plan and hopefully do it right,’’ says Molaro, taking a break from the taping of an upcoming Sheldon episode that features the return of child prodigy (and Sheldon frenemy) Paige (Mckenna Grace).

Before then, expect the arrival of adult Tam (Brian Wu), introduced as a high school student (Ryan Phuong) in Season 1 of Sheldon, along with other crossovers.

‘‘On Young Sheldon, Tam is Sheldon’s best friend, [but] he’s never mentioned him’’ on Big Bang or even invited him to his wedding, says Holland. In the ‘‘Tam Turbulence’’ episode, ‘‘we learn why Sheldon doesn’t talk about him and what happens when we meet the adult Tam.’’

The cast of The Big Bang Theory (from left) Melissa Rauch (Bernadette Rostenkowski), Johnny Galecki (Leonard Hofstadter), Simon Helberg (Howard (Sheldon Cooper), Kunal Nayyar (Raj Koothrappali) and Mayim Bialik (Amy Farrah Fowler).