Jennifer Aniston, Justin Theroux Go To Dinner, Get Upstaged By Michelle Pfeiffer

Jennfer Aniston and her fiance Justin Theroux spent a romantic night out getting dinner at a restaurant in West Hollywood, but despite the presence of the prolific tabloid targets, another celebrity was the center of attention for everyone else in the room.

Aniston and Theroux got dinner at the Madeo restaurant in Los Angeles, but the focus of other people eating in the restaurant was on Michele Pfeiffer, who was also dining there that evening. Maureen Klepfer, who dined at Madeo on the same night, talked with Celebuzz to give the scoop of the celebrities getting dinner and spotting Aniston's enormous engagement ring, which she said looked "ginormous on her tiny hand."

"The funny thing was that everyone was paying attention to Michelle and not Jennifer," Klepfer said.

The onlooker praised Pfeiffer's beautiful looks, which she said are still youthful at 54 years old.

"Michelle looked stunning," Klepfer said. "They were sitting close to Jen's booth. Michelle was with her husband and several friends and they were drinking Opus One," the expensive wine that can cost as much as $200 a bottle.

Although most eyes were on Pfeiffer, that doesn't mean the restaurant's patrons didn't also sneak a peek at Aniston, Theroux and that huge engagement ring, which has been valued at $500,000.

"They were sitting with Chris [McMillan, Aniston's hairstylist] at a super-private corner booth which was dimly lit," Klepfer said. "They were all pretty quiet and mellow. Justin and Jen were both dressed casually - he was wearing all black and Jen was wearing baggy jeans. And Justin is really handsome in person. "After they finished their meal they left quietly out a back entrance."

Aniston has been the subject of many pregnancy rumors over the last few weeks, including a recent report from Star Magazine, which her spokesperson vehemently denied.

"It's just another fabrication," her rep said. "She was just at LACMA and she certainly does not look pregnant. When has Star ever been right?"

Aniston certainly showed no signs of a baby bump when she attended an art gala at the Los Angeles County Museum of Art and wore a revealing Tom Ford gown with a plunging neckline. CLICK HERE to check out photos of Aniston showing off her body at the 2012 Art + Film event.