TJ Watt had a hilarious reaction to seeing his brother JJ Watt in the Acrisure Stadium stands on TNF. The latter cheered himself hoarse in the Pittsburgh Steelers' 20-16 win over the Tennessee Titans in Week 9.

“TJ Watt on his brother at the game: ‘His arm is going to be sore from waving that damn towel,'” per The Athletic's Mike DeFabo.

JJ Watt has been cheering on his brother TJ Watt 

TJ Watt, the Steelers' all-time leader in sacks, has a tendency to play without utter regard for safety. He blindsided Titans quarterback Will Levis with a helmet-less sack in the first quarter of TNF. TJ Watt's insane defensive play prompted his brother to react on social media.

“We don't need no helmet,” JJ Watt tweeted.

Thanks to the Steelers' relentless defense, Will Levis couldn't make any serious headway in his second career start for Tennessee. Bear in mind Levis torched the Atlanta Falcons' secondary for four touchdown passes in the Titans' 28-23 win in Week 8.

TJ Watt's helmet-less sack on Levis was his way of telling the rookie he's not having another career game in their stadium. Levis completed just 22 of 39 passes for 262 yards and zero touchdowns. His costly end-game interception sealed the Titans' fate. Tennessee lost for the fifth time in eight games. On the other hand, the Steelers improved to 5-3 on the season.

JJ Watt is obviously enjoying retirement cheering on his younger brother. The former raved about TJ Watt's legendary pace after the Steelers linebacker had two sacks, two takcles for loss, two quarterback hits, and one fumble recovery against the Baltimore Ravens. With TJ Watt all over the place, the Steelers' limited the Ravens to just 10 points in their Week 5 victory.

Something tells us waving the Terrible Towel will become second nature to JJ Watt as long as his younger brother plays for the Steelers.