Lewis Hamilton Posts Shirtless Selfie, Ready For Race Week!

It's not hard to understand why Kim Kardashian's dating Lewis Hamilton -- the Ferrari superstar popped his top for a shirtless selfie ... and it's got hearts racing.

Sir Lewis shared the photo on his Instagram page Tuesday night ... showing him only rocking a pair of Lululemon shorts as he stood in front of a mirror.

Hamilton's tatted bod was on full display ... and he looks ready to hop behind the wheel when the Formula One season kicks off in a matter of days.

"Race week!" Hamilton said. "I'm ready."

Hamilton made the most of his free time before this weekend's Australian Grand Prix -- as we previously reported, he spent the weekend with Kim at Lake Powell ... staying at Amangiri, a super-lowkey resort in Utah.

The seven-time champion will now be pretty busy with his day job -- the F1 season goes until December ... with a few breaks in between.

Now the real question is -- will Kim be in the Ferrari garage Down Under?? After all, big names always roll through for races.