"It maybe looks like that because sometimes in pictures things look a little... I’m like, what are they talking about?" the Project Runway host continued, showing her bewilderment at the furore surrounding the snap.
Heidi Klum and Justin Bieber at the amfAR gala in Cannes
Speaking to Hamptons magazine at a party, the supermodel also added that the 20-year-old Baby singer was "very polite and very nice."
Heidi and Justin were both at Thursday's world-renowned charity event which has been held each year during the Cannes Film Festival since 1993 and is chaired by Hollywood producer Harvey Weinstein.
Also at the event were current supermodels Jourdan Dunn, Karlie Kloss, and Chanel Iman, as well as Jessica Chastain, Lara Stone, and Marion Cotillard.
Vito, the son of artist Julian Schnabel, is no stranger to dating A-list ladies who are older than him. The New York-born art dealer was romantically linked to 49-year-old Elle Macpherson in 2012 and in 2010 he dated actress Liv Tyler, who is nine years his senior.