So You Think You Can Kiss in Public?

Priscilla Presley has a thing for American idols!

TMZ sources recently spotted the 62-year-old Elvis ex at L.A.'s Brentwood Restaurant and Lounge -- swapping spit with 58-year-old "American Idol" executive producer and "So You Think You Can Dance" judge Nigel Lythgoe. Hound dog!

We're told Priscilla appeared to be enjoying herself -- despite the lack of any facial expression!