Los Angeles, CA (BANG) - Mary-Kate Olsen is dating "Brothers And Sisters" star Dave Annable.

The actress was seen "all over" 28-year-old actor Dave when they recently dined in Los Angeles' Teddy's restaurant in the Roosevelt Hotel.

One diner said, "They were all over each other, they looked as though they couldn't get enough of each other! They were holding hands, cuddling and kissing throughout dinner."

Mary-Kate was first spotted with Dave at Chateau Marmont Hotel's restaurant on December 4 - where they dined with a group of friends including Nicole Richie and DJ Samantha Ronson.

An onlooker told In Touch Weekly magazine, "They drank beer and left together. They looked pretty close."

A representative for 21-year-old Mary-Kate denied the two are a couple, despite the fact that Dave was recently overhead saying he had split from his girlfriend of eight months, Emily VanCamp.

Mary-Kate is following in the footsteps of her twin sister Ashley by securing herself a new man. Ashley was recently romantically linked to "Sweet Home Alabama" star Josh Lucas.