Rocky Carroll will appear on both NCIS and NCIS: Los Angeles this fall.

For at least one episode of the latter, producer Shane Brennan says he won't be the only familiar face on the spin-off: Brennan told reporters last week that Pauley Perrette will appear in episode two of NCIS: Los Angeles.

"She does a crossover and she's directly involved with helping us solve the case. It's a fun little cameo for her," Brennan at the Television Critics Association Q&A session. "We have plans for her to perhaps be in more episodes. And perhaps not just her. I can't tell you yet."

As for the series premiere of the NCIS spin-off, it takes place four months after the events depicts in the NCIS episodes Legend 1 and Legend 2.

"It's Callen's (Chris O'Donnell) first day back on the job, and we see his scars. We literally see his scars," Brenna said. "And he rolls into this new venue and away we go from there. Will we answer what happened to him and how it happened and why? In the very best tradition of NCIS, yes. And in the very best tradition of NCIS, you'll just have to wait. So it will be a sweeps episode. I'll give you that."

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.