NEW ORLEANS -- A Louisiana appellate court is set to hear the case of Cardell Hayes, convicted of manslaughter for fatally shooting retired New Orleans Saints star Will Smith.

Hayes insisted he shot Smith in self-defence after Smith grabbed a gun and fired as the two argued following a 2016 traffic collision. No one else testified Smith held a gun. A handgun was found loaded but unused in Smith's car.

Hayes is serving a 25-year sentence.

Arguments before Louisiana's 4th Circuit Court of Appeal were set for Wednesday afternoon. An immediate ruling was not expected.

Hayes's attorneys say a judge should have granted a new trial because a witness who contacted the defence a day after Hayes' conviction said he had heard two guns at the time of the shooting.