John Luke Robertson, Mary Kate McEacharn John Luke Robertson, Mary Kate McEacharn

The Robertson family is about to get a new member.

Duck Dynasty star John Luke Robertson, the son of Willie and Korie Robertson, got engaged to his girlfriend Mary Kate McEacharn on Saturday, which was also his 19th birthday.

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"She. Said. Yes," John Luke posted on Instagram, alongside a picture of himself holding a sign indicating that McEacharn is "Future Mrs. Robertson."

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She. Said. Yes. @missmarymcmcmc

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McEacharn also posted the picture, with the caption "Happy birthday to the boy I'm going to marry."

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