If there were any doubts that Robin Thicke was an old soul, the smooth soul singer put them to rest with his special collaborative performance with legendary rock group Chicago at the 2014 Grammy Awards.

The "Blurred Lines" crooner, who was up for three Grammy nominations (for the first time), took a trip down memory lane with Chicago. The group entered the hallowed halls of the Grammy Hall of Fame this year for their groundbreaking 1969 debut The Chicago Transit Authority.

Dressed in a bespoke velvet suit and tie, an excited Robin took center stage with a golden microphone and helped the iconic rockers, who won the Best Pop Vocal Performance Grammy in 1976 for "If You Leave Me Now," through a medley of their timeless hits.

Don't get it twisted, though. Whoever thought Robin would just yield the stage to the rock jazz vets don't know how Robin gets down. The blue-eyed vocalist sang the group's songs, "Does Anybody Really Know What Time It Is?" and "Beginnings" along with Chicago frontman and keyboardist Robert Lamm like they were his own.

For the icing on the cake, Robin made his way to the front of the stage to perform the set's crescendo piece, "Blurred Lines." Backed by flashing red graphics, two men on horns and two sultry dancers, Robin turned it up a notch for 2013's most-played song on radio, traipsing down the aisle in front of the stage to get more personal with the audience.

Keeping to his word, though, there were no foam fingers or twerking this time out, just PG flourishes to Pharrell Wiliams' hypnotic beat. As for the exclamation point, that was Robin dropping to his knees, looking skyward and passionately yelling "Woo!" to close out his energetic set.

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