Michael Jackson's children sat in front row seats as the US X Factor celebrated the music of their father last night.

Michael left behind sons Prince, 14, and nine-year-old Blanket and 13-year-old daughter Paris when he died of acute Propofol intoxication in June 2009.

His three young children were joined by their grandmother Katherine and Michael's brothers Jackie, Tito and Marlon on the hit talent show.

The Jackson family watched the themed night and saw the remaining seven contestants pay tribute to Michael by performing a range of his record-breaking hits.

Wednesday also happened to be the 29th anniversary of Michael's record Thriller.

The 1982 album is the best-selling of all time and includes popular tracks including Billie Jean, Beat It and Thriller.

Michael's former physician Dr. Conrad Murray received the maximum sentence available for his involuntary manslaughter earlier this week.

The 58-year-old was ordered by Judge Michael Pastor to spend four years in the Los Angeles County Jail.

Despite receiving the harshest punishment for his crime, Katherine insisted it wasn't adequate.

"Four years is not enough for someone's life. It won't bring him back but at least he got the maximum. I thought the judge was very, very fair and I thank him," she said after the verdict was announced.