Cook County Circuit Court Judge Vincent Gaughan read the 14-count indictment to some 150 potential jurors who packed the courtroom. Gaughan refused to allow reporters to view the proceedings. A court official said there weren't enough seats.
Earlier Friday, Gaughan denied a defense motion to again postpone the trial that already has been delayed for six years.
Defense attorney Marc Martin told the court the jury pool was "irrevocably poisoned" by an article in Friday's Chicago Sun-Times citing unnamed sources talking about a potential witness.
But prosecutors contended it was premature to say the article affected potential jurors and that if any were tainted, they could be weeded out during the selection process.
Publicity surrounding the case has heated up and some media has speculated about who might testify.
Kelly didn't acknowledge the crowd Friday morning as he walked into the courthouse with several other people and a videographer. Raucous onlookers shouted "I love you" and "R. Kelly's a pedophile."
Prosecutors will have to surmount several hurdles if they hope to prevail.
Chief among them is that the alleged victim, now 23, says it wasn't her. And Kelly's lawyers - including prominent Chicago attorney Ed Genson - haven't admitted it's Kelly in the video.
The trial's centerpiece is the video footage, which Gaughan ruled may be shown in open court.
Prosecutors claim the videotape was made sometime between Jan. 1, 1998, and Nov. 1 2000, and that the girl was born in September 1984. Kelly was indicted on pornography charges June 5, 2002, after the tape surfaced.
It is unclear whether prosecutors have asked - or would be allowed - to tell jurors about accusations that Kelly allegedly had sexual relations with other minors, because some of the trial proceedings have been kept secret by the judge.
Media outlets, including The Associated Press, have filed a motion seeking to get court records and hearing transcripts unsealed. Gaughan has said he would rule on that motion May 16.
Gaughan, who has imposed a gag order, also said he would later rule on a defense motion to consider appointing a special prosecutor to investigate apparent leaks to the Sun-Times.
Once the trial gets under way, it is expected to last at least several weeks.
Although he won a Grammy in 1997 for the gospel-like song "I Believe I Can Fly," Kelly's biggest hits are sexually charged songs like "Bump N' Grind," "Ignition" and his current single, "Hair Braider." He is due to release a new album in July.
