According to a 1991 lawsuit, Mad Men star Jon Hamm took part in a violent college hazing incident that happened in 1990 at the University of Texas. The 44-year-old actor was charged with hazing and received deferred adjudication -- which mean he had to complete probation -- but was never convicted.
In the 1991 lawsuit, Sigma Nu pledge Mark Allen Sanders, who was 20 at the time, claimed Hamm set his jeans on fire, shoved his face in dirt and struck him with a paddle. Sanders, who the lawsuit says was left severely beaten after the incident, said Hamm participated in the hazing "till the very end." He said the actor became "mad, I mean really mad" after he failed to recite things he was supposed to memorize about Hamm and other fraternity members.
"He rears back and hits me left-handed, and he hit me right over my right kidney, I mean square over it," Sanders said in the lawsuit. "Good solid hit and that, that stood me right up."
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One of the more disturbing accusations is that Hamm "hooked the claw of a hammer underneath [the pledge's] genitals and led him by the hammer around the room."
Sanders said he needed medical care and withdrew from the school. Court records show the lawsuit was dismissed in 1993, but the Sigma Nu chapter was permanently disbanded following the incident. Four other fraternity members were charged, and pleaded no contest to misdemeanor hazing charges.
School records show Hamm left the University of Texas after the same semester in which the hazing took place.
News of the incident came to light when Star magazine first reported on it earlier this week.
Hamm has been in the headlines recently as Mad Men began airing its final season on AMC. In March, he surprised fans when it was revealed that he completed a stint in rehab for what his representatives said was treatment for alcohol addiction.
He also recently shut down rumors that he split with his longtime girlfriend Jennifer Westfeldt.
"The story that appeared in this week's edition of In Touch magazine is not true," the couple's rep said in a statement to People. "The only gentleman Jennifer visited regularly in Connecticut was Jon, while he was in rehab. They continue to ask for the public's understanding and sensitivity during this challenging time."
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ET caught up with Hamm in March, when he talked about the possibility of a Mad Men movie. Watch below: