Rita Hayworth says: I use Lustre-Creme Shampoo
The pattern
This still is filed under Celebrity endorsement.
Define
A named, recognizable person lends their reputation to the claim. The name is the proof.
Mechanism
Transferred authority. The reader believes the person first, the product second. Fame or office does the work a peer testimonial does not.
Verdict
The endorser is actually known to the buyer
Why it works
The proof is borrowed from a person whose livelihood visibly depends on her hair, which makes the endorsement look like professional practice rather than a paid opinion. Naming the current Columbia release dates and anchors the claim - it is checkable, and checkability reads as honesty. The headline superlative is attached to the star's hair, not to the shampoo, so the brand gets the glamour without having to defend the claim itself. Then the price line, 27 cents to $2, closes the distance: the same jar the star uses costs less than lunch, which is the entire mechanism of the aspirational mass-market testimonial.
Steal this when
Use this when an expensive-looking result is available from a cheap product and you can borrow a credible practitioner who is paid for that result. Show the result large, credit the practitioner precisely enough to be checked, and put the low price next to the pack so the gap between the fantasy and the purchase closes on the page.