Jennifer Love Hewitt compares her 'Criminal Minds' role to Barney Fife

Get ready to meet the newest member of the BAU when Criminal Minds debuts its 10th season.

Ghost Whisperer alum Jennifer Love Hewitt is returning to CBS this fall as FBI Agent Kate Callahan, who will gladly fill the void at the BAU after Blake’s (Jeanne Tripplehorn) sudden exit in the season finale. The team will welcome her with open arms after spending the summer down a man, so to speak. How will she fit in? And what made Hewitt return to broadcast television? EW caught up with the actress to get the scoop.

EW: How did you joining Criminal Minds come together?

I had been on a break for a bit being a mommy. They were looking to add a new cast member and obviously I spent some time at CBS before, doing Ghost Whisperer. Honestly, I had always wondered and been waiting to find the perfect way to get back. My first CBS experience was so awesome. They’re great, and Les [Moonves] has been great to me. I was really excited when they called and asked to take a meeting. I met with [showrunner] Erica [Messer], who I’ve known since I was 14 from Party of Five. I hadn’t seen her in a really long time, so it was great to catch up with her. It all fit and the timing was perfect.

Tell us about Kate Callahan.

Kate is a really interesting woman. She comes to the BAU with her own experience, which I like. I wasn’t quite sure at first if I was going to be a newbie who hadn’t done this before. When they told me about her, I was really excited that she comes with her own background and talent. She had met the BAU team before in an interesting way, which they talk about in my first episode. It’s fun how they’ve all run into each other one other time before Kate gets added to the team. She has a lot of gumption. She’s very feisty. If she’s afraid of a bad guy, she doesn’t show it. She enjoys her job. She really enjoys understanding these people better and getting them put away.

It seems like she fits into the team very well. Is there anyone she doesn’t get along with?

No, pretty much just the bad guy. She has a rapport with everybody on the team. There isn’t a lot of awkwardness with Kate and these characters. She comes in and they remember her very quickly and they get to work. She has a big first day with this team on the job. It’s fun that way. Kate loves really good people in a very sarcastic, feisty way. She has a lot of respect for her comrades and the people she works with. She’s excited to be part of the team.

She’ll be paired up with Rossi (Joe Mantegna) a lot early on. How do they work together?

In the beginning, Rossi is who she’s with the most. I’d say Rossi and Hotch (Thomas Gibson) really are the people she’s with. I always say she’s like the Barney Fife to Hotch’s Andy. She gets really excited to go where he tells her to and be at his side in that way. She and Rossi have a really sweet connection. They have a lot of respect for each other and really enjoy working side by side. I’ve gotten to do a little bit of stuff with Morgan (Shemar Moore) recently, which has been fun. I obviously work with everybody, but those three characters in particular seem to be where I am. Hotch and Rossi are the first two to know Kate’s background story, so they’re very kind to her and supportive of her own personal life story.

Can you say anything about her backstory?

You will get to know it pretty quickly into the season. It’s not like a cliffhanger or anything, but it explains a lot about what some of her triggers will be, why she’s so willing to be feisty and finds real disgust in these people that she has to deal with on a daily basis.

She starts out undercover in the premiere. Is that an expertise she’ll bring to the team more this season?

I hope so. We haven’t done it again yet, but it’s only the beginning of the season. I really had fun with the undercover part of it in the beginning. I’m hoping it’s something she’ll get to use because it is different.

How is this character different from the roles you’ve played in the past?

For me, it’s completely different. Coming off of [The Client List], which was so incredibly different, they couldn’t be more different characters. For [Ghost Whisperer’s] Melinda, there wasn’t a bad guy. Melinda really came up against a lot of super scary people in a totally different way than Kate does. Kate comes up against real life, scary, creepy bad guys. For Melinda, most of the time those people ended up being dead and she was able to find empathy for them. Kate has absolutely no sensitivity for these people just because she believes in the right in people, doing things the right way and not hurting other people. Melinda could understand why these people could do these things and she had to understand in order to get these people to the light. It’s fun, I obviously dress much different on this show than I have in the things that I’ve been in the past and I have a different haircut. It’s the first time I’ve been on a show that I’m not producing and didn’t put together. I’m just a cast member. It’s their house and I’m just really honored to be invited in. It’s fun for me. It’s different in every way possible, but it’s really great.

You brought some great comedy to Hot in Cleveland. Does Kate bring levity to the team?

She does. She has a really fun sense of humor. She’s very sarcastic, and sometimes makes a joke when it’s inappropriate to make a joke. She loves to have zingers with the bad guy, like land something right as she’s leaving the room. It’s a fun part to her. I was really excited that Erica let me bring a sense of humor into this world.

Below, watch a sneak peek of Hewitt in action.

Criminal Minds returns Wednesday at 9 p.m. on CBS.