The former boyfriend of Idols winner Karen Kortje will spend the rest of his life behind bars.

Cheslin Williams was sentenced in the Bellville Regional Court on Thursday.

Two months ago he was found guilty of killing guesthouse owner Renate Kellerman in 2006.

Magistrate JP Vermaak said he could not ignore that the killing was senseless.

He took into consideration the fact Williams was remorseful but felt he had to give the maximum sentence.

The sentence brought to a close a three year-long trial.

Williams showed no emotion but his mother sat in court with red and swollen eyes as the sentence was handed down.