Darth Vader and Luke Skywalker face each other.

With light sabers drawn about to commence an almighty
battle of good over evil.

Suddenly, in the middle of fight Vader pulls Skywalker to
him and whispers:

"I KNOW WHAT YOU'RE GETTING FOR CHRISTMAS,
LUKE. IT'S TRUE, LUKE, I KNOW WHAT YOU'RE
GETTING FOR CHRISTMAS!"

Skywalker tried to ignore this but couldn't in the end.
He wrenched himself free and yells

"How can you know this!?!"

Vader replied "I FELT YOUR PRESENTS..."