Former NFL star Jason Kelce has been filmed smashing a fan's phone after an offensive slur was directed at his brother.

The former Philadelphia Eagles centre was walking through the crowd at a Penn State vs Ohio State College Football match, where he was appearing on ESPN's College GameDay show.

A large number of fans had their phones out and were shouting out at the 36-year-old so he would interact with them.

Kelce, who appeared to be alone, was walking swiftly without interacting until one man could be heard shouting a homophobic slur about his brother, Kansas City tight end Travis.

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The slur was, incongruously, related to Travis Kelce's high-profile relationship with singer Taylor Swift.

Jason Kelce appeared initially to shrug off the comment before turning back, grabbing the phone and slamming it to the ground.

Footage appears to show the man, wearing a blue hoodie and cap, continue to talk right up until the moment his phone is grabbed out of his hand.

Jason Kelce then picks up the phone and walks away without speaking.

It was not immediately clear if the man whose phone was smashed was the man who made the homophobic comment.

However, another video appears to show the man walking after Jason Kelce and asking for his phone back, with Kelce turning towards the man and directing the same slur at him.

Given the seven-time Pro Bowl centre stands at 191 centimetres and had a listed playing weight of 134 kilograms, that appeared to be the second foolish decision the fan made on the day.

Jason Kelce, the older of the two Kelce brothers, retired from the NFL at the end of last season after starting 193 games and won the Super Bowl in 2018.

His brother Travis Kelce and pop star Taylor Swift have been dating for more than a year.

The high-profile nature of the couple, plus a lower-than-average-output from Travis Kelce on the field this season, has led to many supporters criticising the relationship.

The Chiefs, who are 7-0 to start the season, have not been at their best, with Travis Kelce struggling to match his game-leading feats of previous years.

However, just a week after he managed just four catches for 17 yards, Travis Kelce led the Chiefs with 10 catches for 90 yards and a touchdown, his best return of the season.

Jason Kelce has not commented publicly about the incident.