Break out that “NCIS: LA” yearbook, folks. The season 9 premiere will put Hetty’s team face-to-face with an old acquaintance, but it's up to you to figure out who it could be.

Executive producer John Peter Kousakis dropped by the “NCIS: LA” production office on Tuesday and, as the #bestcrewinhollywood prepares to bring the premiere to life, the EP took to Twitter to dish out a few teasers.

An ‘NCIS: LA’ surprise return

Despite the heart-wrenching twists inherent to a season finale, May’s “Uncaged”/”Unleashed” double punch skipped the traditional cliffhanger.

Nevertheless, fans had plenty to ponder over the hiatus. How will Sam (LL Cool J) cope as a single father? When will Deeks (Eric Christian Olsen) and Kensi (Daniela Ruah) walk down the aisle? Now, there’s one more question to add to the list.

“Someone we haven't seen for a few seasons will appear in the premiere,” Kousakis teased, stopping short of revealing an identity. “Can't say more.”

Who could it be? Check out some of the options below:

Director Vance (Rocky Carroll)

Unseen in the LA sphere since season 6’s “Praesidium,” a visit from the NCIS Director is long overdue.

A constant presence on the procedural’s mother ship, Carroll’s crossover could provide a steadying hand after the tumult of season 8.

Marcel Janvier (Christopher Lambert)

A thorn in Callen’s (Chris O’Donnell) side through season 5, Janvier racked up an impressive body count over the years. One of the series’ more infamous villains, the amputee has spent the last few years wasting away in prison.

Perhaps he will fold back into the storyline as season 9 begins.

NCIS Tech Operator John Booker (Andrew Leeds)

If you remember Kensi’s stint in Afghanistan, you undoubtedly remember Booker. Although Nell (Renee Felice Smith) and Eric (Barrett Foa) have the ops room locked down, an extra brain couldn’t hurt.

Mattias Draeger (Jürgen Prochnow)

Dreager’s last encounter with the OSP left a bullet in his knee.

After colluding with the Russians in an attempt to send the diminutive OSP leader to an early grave, the German spy learned not to mess with Hetty’s (Linda Hunt) team. Will he forget that lesson as season 9 begins?

Ray (Channon Roe)

Now that Deeks and Kensi are engaged, maybe it’s time for the detective’s childhood BFF to rise from the dead. A criminal turned informant, Ray caused Deeks to resume an old cover after he slipped out of protective custody in season 2. After the “NCIS: LA” team faked his death (for a second time), Ray headed off into the sunset. What has Roe’s character been up to these last six years? Perhaps we’ll find out.

Next time on ‘NCIS: LA’

Set to return on Oct. 1, the Sunday night drama will jump time slots yet again.

After premiering at 9:30 p.m. ET, “NCIS: LA” will slide to 9 p.m. ET for the rest of the season. Despite the shakeup, viewers can expect the series to keep the stakes high.

“All I can say 2day about S9 NCISLA is...BIG...HEARTFELT...ACTION PACKED and A WHOLE LOT OF FUN!” Kousakis teased.

Dive back into “NCIS: LA” this fall on CBS.