Justin Bieber has a thing for older woman. He's jokingly flirted with Kim Kardashian, Megan Fox, Katy Perry and Cheryl Cole over the last few months. Now, we can add Rihanna to that mix.

But the latter singer didn't simply receive a compliment from the 16-year old... she got an up-close and personal peek at his bare flesh!

hands to yourself, Justin. Eyes to yourself, Rihanna. At least wait a couple years, sheesh! [Photos: Splash News]

On Monday night, Rihanna, Justin, friends and a record executive had dinner in Los Angeles. During the meal, "Justin started bragging about how he has abs," a source told Us Weekly.

When Rihanna joked about seeing them, the singer obliged!

"Justin took off his jacket, glasses and lifted up his shirt," said an insider. "Apparently he does have a little 6 pack!"

But don't just take this anonymous person's word for it. Rihanna herself Tweeted after the meal:

Justin Bieber just flashed me his abs in the middle of a restaurant! Wow! He actually had a lil 6 pack! Sexy,lol!

Look out, Matt Kemp. You might wanna feel your girlfriend's forehead. Someone is coming down with a serious case of Bieber Fever!

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