The trial of R. Kelly lived up to its billing as the biggest show in town last week as it finally began with three days of explosive testimony.

Facing up to 15 years behind bars if convicted, the R&B star is charged with 14 counts of child pornography.

Wearing expensively tailored suits, he sat mostly expressionless in court as prosecutors laid out details of how he allegedly videotaped himself having sex with — and urinating on — a girl as young as 13, sometime between 1998 and 2000.

By turns sordid, disturbing, bizarre, unintentionally funny and sad, the dramatic testimony has rivaled the script of any TV show.

The trial began quickly, with Cook County Assistant State’s Attorney Shauna Boliker saying Kelly “created, staged, produced and starred” in the infamous sex tape.

Defense attorney Sam Adam Jr. countered that neither Kelly nor the alleged victim is on the tape.

The case was “simple,” he said, adding that the alleged victim would not be testifying for the prosecution.

Adam also pointed to pictures of a mole on Kelly’s back that Adam claims does not appear on the man in the sex tape.

Later, court staff played the tape for the jury on a large screen.

Kelly looked sad as the tape showed a girl accepting money from a man, performing oral sex on him, dancing naked and urinating at the man’s command, then calling him “Daddy” while they have sex.

He put his hand to his head as the tape showed the man urinate and ejaculate on her.

On Wednesday, the alleged victim’s former best friend, Simha Jamison, testified that she was sure it was the alleged victim and Kelly on the tape.

“I know her like the back of my hand,” she said, adding that she’d often seen Kelly hand the alleged victim cash.

Jamison said she had cried herself to sleep after seeing the tape.

Four other Oak Park residents have testified that it is Kelly and the alleged victim on the tape. Kelly’s attorneys argue that none was close to Kelly or the alleged victim by the time the tape surfaced, saying the identifications were based on neighborhood gossip.

They also say three relatives of the alleged victim who identified her and Kelly on the tape were motivated by greed.

One of those relatives, singer Stephanie “Sparkle” Edwards, testified Thursday that she had introduced the alleged victim to Kelly, and that the girl called him her “Godfather.” Kelly helped Sparkle’s career early on, but the pair later parted ways.

Defense attorney Ed Genson suggested that she resented Kelly and wanted revenge for their split.

But insisting her family had been “thick as thieves” until this case ripped them apart, she again insisted it was her relative on the tape.

“I know my family!” she said.

With another three weeks of testimony likely, and the defense yet to present its case, many questions remain unanswered.

Will the alleged victim testify for Kelly, as has been hinted at, telling the jury it is not her on the tape?

And what about the Atlanta woman expected to testify that she took part in a threesome with Kelly and the alleged victim?

The case continues Tuesday.