Though he was spotted at a Los Angeles gym with a mystery brunette for the past week, Robert Pattinson has been dating model Dylan Penn for some time now.

Two eyewitnesses spotted Pattinson on dates with Penn and spoke to Life & Style Weekly about the sightings, reported Wednesday. The model, whose is the daughter of Hollywood actor Sean Penn and actress Robin Wright, was seen being affectionate with the British actor in public and at a private gathering in his home.

An eyewitness saw the pair at Los Angeles' nightclub Viper Room on Sept. 7. The onlooker said they were "touchy-feely and very flirtatious," gave away several hints indicating that they have been dating for some time now. They were so comfortable with each other that it was obvious it wasn't their first date.

"There was a level of comfort there," said the eyewitness. "You could tell they've hung out a few times."

Their date didn't end there -- Pattinson later took Dylan to Chateau Marmont for drinks and French fries, added the insider. He had a car waiting for them to go club-hopping afterwards.

Another source told the publication they and a group of friends spent time at Pattinson's home in a previous occasion.

"They went into his kitchen, and he put his arms around her. Then he was kissing her neck and talking all lovey-dovey. It was clear they'd been out together before." When fellow guests left at 5 a.m., Dylan was still there," said the second eyewitness.

The insider added that Pattinson should be careful because Penn's father is known for his hot temper and has high standards for his daughter.

 "Any guy who dates Dylan should watch his back and treat her right!" said the source.

Robert Pattinson With Mystery Brunette PHOTOS, Leave Gym Together Days After Party PDA Spotting  

Pattinson and a brunette were photographed leaving a gym at the same time but separately on Monday. The pair drove off in the same car together, according to an eyewitness.

"Rob rarely hangs out with a girl he's not dating. He keeps to himself. So they fact they left in the car together definitely means something," the onlooker told X17Online.

He was also seen displaying public affection with a mystery brunette over the weekend. Pattinson held hands with an unidentified woman at a birthday party for actress Shoshana Bush in Los Angeles.

"Rob and the brunette turned up around midnight. They were cute together," an onlooker told RadarOnline. "At one point, he was talking to someone and she wandered over and grabbed his hand and pulled him to over to near the pool. Their hands were all over each other!"

Robert Pattinson & New Brunette Girlfriend Display Heavy PDA At Party 

Pattinson reportedly ended his four-year relationship with Kristin Stewart in mid-May following his 27th birthday. 

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