Wilmer Valderrama has let the cat out of the bag on a new NCIS guest star.

Currently, there's lots of buzz about a possible "Gibbs" (Mark Harmon) comeback in the near future. But let's get it out of the way: it's not "Gibbs." Even so, fans are excited about the star, who hasn't appeared on the show in several seasons...

NCIS season 19: Surprise guest star confirmed

On Thursday, Valderrama took to Instagram for the reveal. In the video, the "Torres" actor says: "I'm here on the set of NCIS and I think I might get in trouble for this one, but I'm just gonna pan over..."

He points his camera to the side, revealing actress Meredith Eaton on the NCIS set. "Oh hi! How are you?" she asks, as Valderrama laughs and signals to keep it a secret.

Fans will remember Eaton for playing "Carol Wilson" in previous episodes of both NCIS and NCIS: New Orleans. She works with the Center for Disease Control, and she's also a former colleague of "Abby Sciuto."

"Carol" was last seen in a season 11 episode of NCIS — so it's been a while! Presumably, she won't appear in the next episode, which airs on Dec. 6, as the series likely films episodes weeks in advance.

After that, NCIS isn't back until the New Year. So expect to see actress Meredith Eaton on the show in 2022.

NCIS: Meredith Eaton will appear as "Carol Wilson" in season 19.

Eaton, 47, is also known to TV fans for her roles on Boston Legal and most recently MacGyver. Her upcoming appearance will also follow a few other notable NCIS guest stars this season.

Home Improvement actress Patricia Richardson recently appeared as the mother-in-law of "McGee," and fans saw Don Swayze (the brother of Patrick) in the latest episode.