WARNING: This article may contain spoilers for NCIS: Los Angeles season 11 episode 15. Read at your own risk.

NCIS: Los Angeles season 11 episode 15 is arriving on CBS within a few weeks, with the title "The Circle." This will be an exciting episode as it marks the returns of two characters: Anna returns to warn Callen, while Hetty is also back, though the reason isn't clear right now.

Previously, CBS confirmed Bar Paly is returning as Anna in the upcoming NCIS: Los Angeles season 11 episode 15. She's been frequently mentioned this season, as Callen is willing to do everything he can just to track her down. Although her whereabouts were unknown, he is determined to find her.

Now, in NCIS: Los Angeles season 11 episode 15, Anna returns but with a very particular reason. She came back to warn Callen that he's in danger and that he should start working with an archenemy to stop an underground trafficking ring. She's going to have an important role in this episode.

However, it's not yet confirmed whether or not Anna will be sticking around after the episode. Yet, many were also hoping she and Callen will have some romantic moments. The two have a history together and Callen has gone through so much and he now realized who he wants to be with.

Meanwhile, Linda Hunt's Hetty is also coming back in NCIS: Los Angeles season 11 episode 15. The character hasn't been in every episode, with some even speculating she may not be coming back at some point. She was last seen on the episode written by Eric Christian Olsen and her role, at that time, is significant.

Now, viewers will see her once again, possibly with another big role, as it was confirmed she's coming back in the upcoming episode 15. But, what would be her role this time? It remains unclear right now, but CarterMatt noted she probably returns to help Anna and Callen.

In a related report, the series has already hinted at Hetty's eventual retirement. Hunt is also turning 75-years-old this year. So, it wouldn't be a surprise if she's leaving the show at some point. In 2013, the actress revealed to CBS' Sunday Morning host Lee Cowan she doesn't mind leaving the series. "I look forward to a time when I don't have to work anymore," she said.

NCIS: Los Angeles season 11 episode 15 airs on Sunday, Feb. 23, on CBS.