Sentencing has been postponed for the man who pleaded guilty to pushing a stranger in front of a moving Bronx subway train two years ago, killing him as his wife looked on in horror.

Kevin Darden, 36, was supposed to be sentenced Tuesday, but the court hearing was delayed because he was sick, officials said.

Darden previously copped to a manslaughter charge in exchange for a lesser prison sentence in the Nov. 16, 2014 death of 61-year-old Wai Kuen Kwok, who was standing with his wife on the southbound D platform at the Grand Concourse and East 167th Street station when Darden shoved him in front of a train.

Police say Darden and Kwok didn't know each other. Darden, who had previously been charged with murder, faces 18 years in prison under the plea deal. 

Surveillance video showed him calmly leaving the scene after the attack. 

Darden has a lengthy criminal record, including a 2011 arrests for trying to burn his brother's Texas home down and a 2014 arrest for pickpocketing near Times Square, according to DNAInfo.

He was released from jail two days before pushing Kwok in front of the oncoming train.