Annette Funicello, who won America’s heart as a 12- year-old in Mickey Mouse ears, captivated adolescent baby boomers in slightly spicy beach movies and later championed people with multiple sclerosis, a disease she had for more than 25 years, died Monday in Bakersfield, Calif. She was 70.

Her death, from complications of the disease, was announced on the Disney website.

As an adult Funicello described herself as “the queen of teen,” and millions around her age agreed. Young audiences appreciated her sweet, forthright appeal, and parents saw her as the perfect daughter.

She was the last of the 24 original Mouseketeers chosen for “The Mickey Mouse Club,” the immensely popular children’s television show that began in 1955, when fewer than two-thirds of households had television sets. Walt Disney personally discovered her at a ballet performance.

Before long, she was getting more than 6,000 fan letters a week, and was known by just her first name in a manner that later defined celebrities like Cher, Madonna and Prince.

Sometimes called “America’s girl next door,” she nonetheless managed to be at the center of the action during rock ’n’ roll’s exuberant emergence. She was the youngest member of Dick Clark’s Caravan of Stars tour, which included LaVern Baker, the Drifters, Bobby Rydell, the Coasters and Paul Anka. Anka, her boyfriend, wrote “Puppy Love” for her in her parents’ living room.

She said if she had charm (she undeniably had modesty), it was partly a result of her shyness. Disney begged her to call him Uncle Walt, but she could manage only “Mr. Disney.”

At the height of her stardom, she said her ambition was to quit show business and have nine children.

With minor exceptions, like her commercials for Skippy peanut butter, Funicello did become a homemaker after marrying at 22. One reason, she said, was her reluctance to take parts at odds with her squeaky-clean image.

Annette Joanne Funicello was born on Oct. 22, 1942, in Utica, N.Y., and as the first grandchild on either side of the family was indulged to the point of being, in her own words, a “spoiled brat.” At age 2, she learned the words to every song on the hit parade, her favorite being “Ac-cent-tchu-ate the Positive.”

In 1946, her parents decided to move to Southern California in the hope of doing better economically. They lived in a trailer park until her father, a mechanic, found work. They settled in Studio City and later moved to Encino.

Annette took dancing lessons, learned to play drums and, at 9, was named Miss Willow Lake at a poolside beauty contest. She did some modeling. Disney, who wanted amateurs and not professional child actors, discovered her when she danced in “Swan Lake” at a local recital.

In 1958, as “The Mickey Mouse Club” was ending its run, Disney summoned Funicello to his office. She feared she was going to be fired for growing too tall, but instead he offered her a studio contract — the only one given to a Mouseketeer.

On Jan. 9, 1965, Funicello married her agent, Jack Gilardi. Charles M. Schulz in his “Peanuts” comic strip showed Linus reading a paper, clutching his security blanket and wailing: “I can’t stand it! This is terrible! How depressing. … ANNETTE FUNICELLO HAS GROWN UP!”

She made a few films in the middle and late 1960s, including “Fireball” and “Thunder Alley,” but her attention was focused on her children, Gina, Jack Jr. and Jason Michael. During the 1970s and early 1980s, she appeared occasionally on TV but was known principally for commercials, including her memorable issuing of the Skippy peanut butter challenge: Which has more protein? (Bologna and fish were not the correct answers.)

Funicello learned she had MS in 1987 but kept her condition secret for five years. She announced the illness after becoming concerned that the unsteadiness the disease caused would be misinterpreted as drunkenness.