Katharine McPhee Sunbathing in Capri for Honeymoon

Katharine McPhee and David Foster are putting themselves in serious contention for best honeymooners in this summer of newlywed celeb love ... just look at them!!!

KM and DF are soaking up the sun during their post-wedding getaway off the coast of the gorgeous Italian island of Capri. Yacht style, the only way to go! Kudos to the groom ... not for his swimwear, but for getting Katharine to say, "I do." Her beige bikini highlights what we already knew ... she's an absolute spettacolo di fumo (that's Italian for smoke show)!!! 

Kat started out in a sun dress, and then stripped down to her two-piece as she laid out on the boat ... eventually even going topless while tanning next to her hubby. 

BTW, Dave and his new bride appear absolutely gaga for each other under the Italian sun -- like we said, Chris Pratt and Kat Schwarzenegger might have some competition on the most affectionate couple in Hollywood. Joe Jonas and Sophie Turner too, for that matter ... who also happen to be honeymooning in the area.