Sienna Spiro was something of an established artist even before her debut full-length album, “Visitor,” came out on July 3. The 20-year-old Londoner with the big ’60s hair and an even bigger, more timeless voice is officially a freshman — she will almost certainly be up for a best new artist Grammy in a few months — but she’s also already a role model.

Not that this has occurred to her yet. “Really?” she says when I point out this dichotomy over a Zoom call shortly after the record’s release, a little bit surprised that anyone could consider her an influential or entrenched figure in pop music just yet.

So here’s the case for her already being a star, and a true influencer: The new LP was preceded by a series of star-making singles, like the glorious ballad “Die on This Hill,” which went Top 20 in America and Top 10 in her native U.K. That led to a series of media-galvanizing shows, like a U.S. headlining debut in L.A. at the Troubadour in March that had me raving about her in Variety as “the world’s next great pop vocal superhero.” A tour of bigger North American theaters set for this October sold out immediately, with her album not yet released, as skyrocketing resale prices suggested that the amphitheater circuit would have been within reach for her.