Although Jessica Walter has been a regular fixture on TV for

over four decades, earning an Emmy for the 1974 miniseries, Amy Prentiss, Walter’s most popular work

has been on two short-lived, cult series, Dinosaurs

and Arrested Development. However, FX’s

animated series about a spy agency, on which she voices the matriarch, a seemingly

always-drunk Mallory Archer, is proving to surpass both.

“I’ve never been in a show that’s lasted that long,” Walter tells

ETonline about Archer, which returns

on March 31 for its seventh season.

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The series -- which again, dispenses with its original

concept for a revamped concept about private detectives in Los Angeles -- has continued

to earn new diehard fans with each new season. And Walter says this year will

be no different, despite any reservations over its Magnum, P.I.-inspired makeover.

“It's a fresh take on everything,” the 75-year-old actress

says. “There is a lot of fun to be made of Hollywood and private eyes.” For

Mallory, she will find herself no longer in charge as her former agency of

spies goes from hired CIA hands to a private investigative agency. The character

will also go undercover as a Hollywood producer to protect a film from

sabotage.

FX

At one point in the premiere, Mallory admonishes Cyril

Figgis (Chris Parnell), a comptroller turned head of The Figgis Private

Detective Agency, for not embracing all the changes, as if to tell the audience

to do the same.

For Walter, she welcomes the character development just the

same as she would for Lucille Bluth, another seemingly drunk matriarch on Arrested Development. “I look at it as an

acting challenge, which is the most important part,” Walter says, revealing she

even pitched ideas for Mallory to creator Adam Reed.

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What ideas exactly? It’s unclear, except that she says “it’s

going to be beyond.”

As for Arrested

Development, of which executive producer Brian Grazer said a fifth season was

coming in 2016, one year after Netflix’s chief content officer Ted Sarandos

said it was “just a matter of when,” Walter has even less to offer.

“We heard we were

going to do it, but that was a few months ago,” she says. “But since then, I

haven't heard a word.”

Netflix has no comment to ET about the status of the series.

However, she’s fully committed to doing the show as long as

fans want it to continue. “I think everybody agrees: we'd love to do more. Absolutely,”

Walter says. “I love that show. It was so important to me in my career.”

In the meantime, fans can relish in Archer, which has also served as a reunion place of sorts for the AD cast. While Judy Greer co-stars as

Cheryl Tunt, Jeffrey Tambor and David Cross have made guest appearances.

And, as if knowing she hasn’t teased fans enough, she offers

one final tidbit about the future of Archer,

assuming it gets renewed for season eight: “I’ve got to tell you, it’s going to

be different next year,” she says of Mallory’s appearance. “That’s all I can

say.”

FX did not confirm if the serieshas been renewed for season eight.