Martha Stewart and Bella Hadid are fans, too. Andie MacDowell is at the 2025 Cannes Film Festival, celebrating her 40th(!) anniversary as a L’Oréal ambassador. This marks the brand’s fourth ...

Shop MacDowell’s red carpet secret to full, soft, healthy-looking hair, the L’Oréal Elvive Hyaluron Plump Hair Serum, while it’s $8 at Amazon. Consider similar options, below.