Mr Kelly faces up to 15 years in jail if he is convicted
Dramatic claims of a potential new defence witness have interrupted the trial of US R&B singer R Kelly on child sex charges.
A lawyer for Mr Kelly informed the court in Chicago that the defence had not known about the new witness until he called them on Wednesday morning.
The judge halted the trial for a day to allow time for the man to fly in from another state and make a deposition.
"I have no idea what's going on," Judge Vincent Gaughan told the court.
But he confirmed that testimony in the trial would resume on Thursday morning.
Mr Kelly is charged with 14 counts relating to child pornography in connection with a 26-minute video, believed to have been made between 1998 and 2000.
It features explicit acts of sex between an adult man and a girl believed to be aged about 13.
The singer denies filming himself having sex with an underage girl and his lawyer insists that neither his client nor the alleged victim are on the video.
His alleged victim, now 23, has also denied she is the girl in the video.
'Nine o'clock call'
Earlier on Wednesday, the court heard testimony from two prosecution witnesses - a basketball coach and a former basketball coach - who said they could identify the female on the video.
Defence lawyer Sam Adam Senior said his team had not been aware of the potential new witness's existence until he phoned them at 0900 that morning.
If necessary, he added, the defence would interview him into the early hours of Thursday.
Announcing an adjournment, Judge Gaughan said the mystery witness might be seeking to impeach a witness for the prosecution.
Since prosecutors began presenting their case last week, they have called more than a dozen witnesses.
Mr Kelly, 41, whose hits include She's Got That Vibe and I Believe I Can Fly, faces up to 15 years in jail if convicted.
The tape was originally posted to the Chicago Sun-Times newspaper in 2002. The paper then handed it to police.