No BLURRED Lines Here — This Is CROSSING It! Married Man Robin Thicke Caught Groping Hot Blonde

Miley Cyrus isn't the only woman whose rear-end has been getting some extra attention from Robin Thicke in recent days.

The married dad was recently snapped in a friendly clinch with a hot blonde -- but the mirror behind them revealed Robin's X-rated intentions!

The reflection captured the Blurred Lines singer's hand creeping up the back of the woman's skirt as he groped her butt cheek with a grin on his face!

The photo is believed to have been taken at NYC nightclub 1OAK, where Robin hosted an after-party following his MTV VMA performance with Miley on Sunday night. It was posted on social media.

Other official shots from the night show Robin, 36, wearing the same pinky ring on his right hand and what appears to be the same tuxedo shirt and jacket.

And even though Robin's wife, Paula Patton, was nowhere to be seen as he got up close and personal with the blonde, she was spotted elsewhere in the club, partying by his side all night.

Paula, 37, was also on hand when Robin partied with twerk fiend Miley on Friday night in the city, RadarOnline.com has learned exclusively, hitting up the Darby and 1OAK before calling it a night.

Indeed, all appeared well between the couple as they frolicked on the beach with their son, Julian, in Miami on Wednesday.

But Robin does have a history of blurring the lines of monogamy: As RadarOnline.com reported, he hit on married Playboy model Amy Varela back in 2012.