The rehearsal that was supposed to take place at 4pm was delayed slightly, with the singer arriving at around 5:30pm clad in a white t-shirt, multi-colored training pants and sneakers.
The 50-year-old singer, dancer and actress arrived in Israel on Tuesday and went straight to the Dan Hotel in Tel Aviv.
She is staying in the hotel's royal suite with her partner, former baseball star Alex Rodriguez, and her 11-year-old twin children. Lopez spent Wednesday night at a restaurant in Tel Aviv, and the morning at her hotel.
"She is devoid of pretension," said sources involved in her visit to Israel.
"We haven't seen such a nice artist for a long time. She is great."
With tickets still unsold for the single Tel Aviv performance, the production expressed concerns that people had been conned into buying fake tickets online.
They cautioned people to buy tickets only from Le'an - the sole agency licensed to sell them.
"Anyone who has purchased fake tickets will not get in to see the show," the production said.
The show, which is set to begin at 8:45pm, is part of the pop star's "It's My Party tour," which began in June.
The tour only includes six countries outside the United States – Israel, Canada, Russia, Spain, Turkey and Egypt.
Lopez is expected to leave Israel on Saturday. Her next performance will be in Moscow on August 4.