“The Adventures of Rocky and Bullwinkle” executive producer Scott Fellows knew a voice was missing when the casting team replayed the audition tapes for the show’s titular flying squirrel. “Where’s Tara Strong?” he asked.

Strong had submitted voice auditions twice for the character of Rocky — once for the initial call, which proved unsuccessful, and another when her agent told her Rocky would be recast. Until Fellows inquired, casting agents had pushed her auditions aside. But upon hearing her tape, they immediately changed their minds.

“This is no fault of any studio, but a lot of times they say, ‘Oh that actor’s on everything, so let’s try new blood,'” Strong tells Variety. “Which truthfully is silly because voice actors who work all the time do so because they’re versatile, and sometimes you have no idea it’s that person.”

If the “Rocky and Bullwinkle” creative team was looking for a newcomer, their early decision to eliminate Strong from the pool makes sense. Before accepting the role in Dreamworks Animation and Amazon Prime’s upcoming revival of the beloved animated series about a moose and squirrel spy team, Strong had already lent her voice to hundreds of characters for more than 30 years, ranging from Bubbles in “The Powerpuff Girls” to Timmy Turner in “The Fairly OddParents,” where she first met Fellows.

“I’ve been so lucky,” Strong says. “I don’t know what horseshoe I was born under, but who gets to say they played Batgirl and Harley [Quinn] and Timmy Turner and Raven and Bubbles?”

Despite her now extensive voice acting resume, Strong never planned to devote so much of her professional life to voiceover. She knew she wanted to act from a young age, but her vocal interests were limited to pulling funny tones and accents for family members growing up in Toronto, Canada. Up until she landed her first voice role as Hello Kitty, Strong never considered animation acting as a career.

“The experience of changing my voice and creating characters came along organically when I started performing,” Strong says. “I didn’t know that was gonna be my main thing, and it’s just kind of how it went. And yeah, the rest is history.”

They key to dissolving oneself into an animated character of any gender, age or species is to study the concept material, predict the creators’ vision, and craft a persona that can stand alone, Strong says.

“They live up in my brain, and they come down to play,” Strong says of her character repertoire. “I can’t really describe why you don’t confuse them, but they become their own real person living in my brain.”

Though Strong has herself originated several voices, like “Ben 10’s” Ben Tennyson and “Teen Titans'” Raven, stepping into the role of Rocky meant continuing a legacy started by the voice of the late June Foray almost 60 years ago. With the blessings of “Rocky and Bullwinkle” creator Jay Ward’s daughter and granddaughter, Strong sought to pay homage to Foray’s Rocky while adding a little bit of her own personality.

“Those are some big shoes of a wonderful little woman to fill, and she really brought joy to so many people for so many generations, so it was pretty daunting,” Strong says. “I knew how iconic this character was and how beloved June was, so it’s scary.”

In the early stages of the revival, the creative team wanted Strong to age Rocky slightly by giving him a deeper tone and making him sharper, more sarcastic than before. But by the time Strong recorded the fifth episode, the flying squirrel had naturally returned to its bubblier roots.

“As it went on, it became more June,” Strong says. “Even as she passed, it was kind of like she took over and said, ‘This is how it’s supposed to be.’”

While recording for Rocky, Strong provided support to Brad Norman, who voices Bullwinkle, much like Rocky does for his moose friend. Bullwinkle is Norman’s first starring voice role, and Strong offered him her guidance as a voiceover veteran, taking him to lunch and encouraging him to recognize his talent and natural comedic timing as Bullwinkle.

“So much of it is confidence, and if you don’t have it, you have to be really good at pretending like you do,” Strong says. “I wanted him to have all the confidence in the world knowing that he was phenomenal and knowing that Jay would have been proud.”

Strong has grown accustomed to working with voiceover newbies over the years. Some, like Norman, she says, possess an organic embodiment of their characters, while others miss the mark. One major change Strong has witnessed during her time as a voice actress has been the growing popularity of voice roles for those she terms “on-camera celebrities” who want to step into the cartoon world.

While certain stars, like her “New Batman Adventures'” cast mate Mark Hamill, immediately impressed Strong with their vocal abilities, she says many become overwhelmed by the intricacies of the craft, never to return to the booth again.

“You’re asking a tap dancer to do ballet, and not everybody does both,” Strong says. “It’s acting, but it’s a different side, and really, people that get great at it do it all the time.”

“The Adventures of Rocky and Bullwinkle” streams on Amazon Prime Video May 11.