They're so perfect, it's nauseating.

Tall, blond Leonardo DiCaprio was seen holding hands with tall, blond Blake Lively in Italy over the weekend, just days after they were spotted hugging on a yacht at the Cannes Film Festival.

Blech.

The only potential problem for this impossibly good-looking new couple? DiCaprio is 36 and Lively is 23, creating a sizable 13-year age difference.

SODAHEAD SLIDESHOW: See the sexiest celebrity couples.

DiCaprio also happens to be on the rebound. He just split with 25-year-old Israeli supermodel Bar Rafaeli, and they're known to be on-and-off.

"They do this every two years," a source told Us Weekly. "They could be back together next week."

In the meantime, from Leo and Blake to Brangelina to Gisele and Tom, let us know: Who's the sexiest celeb couple?