The iPhone’s “buzz” got a bump after Apple started using celebrities in its Siri ads

FORTUNE — Some purists used the fact that Apple (AAPL) had replaced the always appealing but generally anonymous faces in its TV ads with a couple of Hollywood celebrities — Zooey Deschanel and Samuel L. Jackson — as evidence that the company had gone to hell without Steve Jobs at the helm. (See Siri takes a star turn.)

But a new YouGov BrandIndex survey suggests that Apple marketing may still know how to do its job.

According to a report issued Tuesday, the Siri ads featuring Deschanel and Jackson coincided with a boost for the iPhone brand among the all-important demographic of 18-34 year old Americans:

“Just as the new Siri campaign premiered on April 19th, iPhone’s buzz score in the 18 – 34 demo was 16, several points below Android’s 26 score. Five days later, iPhone’s buzz score passed Android, 30 vs. 29… The iPhone’s buzz score peaked on May 4th with a 51 score, while Android moved a couple of points down to 27.”

Both men and women responded positively to the ads, according to YouGov, but men registered the strongest push.

[Read methodology, sources, and further results at Fortune.com]