Harry Styles and Zoë Kravitz going from ‘0-60' in romance

Harry Styles and Zoë Kravitz’s alleged relationship is not just a fling, says an insider.

The couple, who was spotted strolling on the streets of California this week, are serious in their romance.

A Hollywood insider tells Page Six: “I feel like they’ve gone from 0-60.”

“It’s so hard to date as a celebrity … Harry wouldn’t have gone public with Zoë if it wasn’t anything,” said the source. “(But) it’s very new and fresh and they’re just having fun.”

The source added: “Harry doesn’t label this stuff.”

Meanwhile, insiders told RadarOnline about Kravitz: “She's bold, self-assured and has this undeniable pull. People close to him believe she might be the only one exciting and captivating enough to get him to leave his playboy image behind.”

“He's showing more effort with her than he ever has before, and that speaks volumes,” they added.