He tweeted a congratulations to his brother Derek Watt and his wife.
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The Los Angeles Chargers fullback posted a photo of his new baby with the caption, "what better way to spend our first wedding anniversary than welcoming our son, Logan James Watt, to our family!"
It looks like J.J. and T.J. Watt can add L.J. to the bunch! Derek's middle name is John, but he doesn't go by D.J. All three brothers play in the NFL.