"I am," the famous 84-year-old said from the glass-walled dock at Southwark Crown Court.
Harris denies indecently assaulting four girls, one as young as seven or eight, between 1968 and 1986.
The man who gave the world the wobble board earlier arrived at court accompanied by his wife, Alwen, and daughter Bindi.
Dressed in a dark blue suit, white shirt, red braces and a colourful tie, Harris was protected by private security personnel.
The artist held his wife's hand as they walked slowly past a large media pack into the court.
The pair smiled and chatted together but Harris offered no comment to reporters.
Inside, the 84-year-old carried what appeared to be a lunchbox with him as he took his place in the dock.
He listened to proceedings with the aid of a hearing loop.
During numerous delays, Harris chatted with a court officer.
At one point he closed his eyes as if asleep.
Justice Nigel Sweeney told potential jurors that sitting in judgment on a fellow citizen was "one of the most important duties that any of us can be called upon to perform".
He said they should have no prior connection to the case so they could "reach true verdicts based on the evidence rather than any preconceived ideas, beliefs or prejudices".
Potential jurors were excused if they had family or friends who lived in Australia or New Zealand or would be visiting in the next few months.
Justice Sweeney said the evidence "includes events in Australia and New Zealand".
Harris in mid-January formally pleaded not guilty to 12 counts of indecent assault in the UK against four girls aged between seven and 19.
He is also facing four counts of making indecent photographs of a child in 2012 but is yet to be arraigned on those charges.
The trial is expected to take two months and hear from dozens of witnesses.
It's likely the prosecution will open its case later this week after the jury of 12 is finalised.
The trial continues.
- AAP
