There won't be any tan lines for Heidi Klum.

The 42-year-old supermodel took a break from the red carpets at the Cannes Film Festival on Wednesday to spend the day beachside in Pampelonne, Gulf of Saint-Tropez with her boyfriend, Vito Schnabel. While Klum shielded her face from the sun with a hat and dark sunglasses, she was only wearing a string bikini bottom, sans top.

Her 29-year-old beau didn't seem to mind as they giggled and embraced in the Mediterranean sea.

WATCH: Heidi Klum and Boyfriend Vito Schnabel Pack on the PDA During Romantic Caribbean Getaway

After the PDA-filled excursion in the sun, Klum was back on the red carpet for Thursday's amfAR's 23rd Cinema Against AIDS Gala at Hotel du Cap-Eden-Roc. Stepping out in a thigh-baring yellow gown, Klum mingled with her fellow supermodels at event, including Petra Nemcova and Alessandra Ambrosio.

MORE: Heidi Klum Shows Off Her Butt-Baring Wardrobe Malfunction 

"Looking forward to joining @amfAR tonight!" she Instagrammed prior to the event. "Proud to be supporting the fight to end #AIDS #amfARCannes"

While Klum -- who was married to her second husband, Seal, from 2005 to 2014 -- has never looked happier while in Cannes with her beau, she insisted when she spoke to ET last year that she does not want to remarry. "I won't get married again," she said decisively. "People always write all these crazy things, but it's not all true. Don't always believe what you read in the paper!"