The twosome shared an intimate dinner at Little Dom's in Los Angeles' Los Feliz neighborhood on Aug. 2. According to a fellow diner, Williams, 27, and Jonze, 38, started off their late-night meal sitting across from each other. "During dinner they would lean in and kiss each other over the table," the diner says.

By the end of the meal, Williams had hopped into Jonze's lap and the pair were smooching, according to onlooker.

Jonze, the ex-husband of Sofia Coppola, produced the actress' upcoming film Synecdoche, New York. At the Brooklyn deli, the director "had his arm around [Williams] and kissed her on the cheeks, then on the lips," PEOPLE reported recently.

Reps for both had no comment.

(Source: People)