President Donald Trump will address around 800 US and Israeli dignitaries at the ceremonial opening of the American embassy in Jerusalem by video on Monday, the US ambassador said.
It was not immediately clear from Ambassador David Friedman's comment, on a call with reporters, whether Trump would speak via a live videolink or a pre-recorded address.
"Big week next week when the American Embassy in Israel will be moved to Jerusalem. Congratulations to all!" Trump tweeted on Friday.
The ambassador said staff at the Tel Aviv mission had just marked its last day as an embassy and some of them would turn up for work on Monday at the Jerusalem embassy, which would host an opening ceremony later that day.
"People will be coming back to work as the embassy branch of the Jerusalem embassy, and I think we're all very happy and excited to be participating in such a historic event," Friedman said.
"People have been working literally around the clock in getting ready for our opening dedication ceremony on Monday. We'll be ready."
Friedman said around 800 people were expected for the ceremony, he added, explaining that in addition to the previously announced US presidential delegation, a "healthy number" of American lawmakers were also set to attend.
"The president, from my side of things, will be addressing the audience by video," he said.
Lindsey Graham's office said he would be among a delegation of senators, also including Ted Cruz, who would attend the opening ceremony and meet with Israeli officials about "counter-terrorism and national security issues."
But he stressed the event will be a bilateral US-Israeli celebration, downplaying reports that very few if any diplomats from other countries that have not recognized Jerusalem as Israel's capital would attend.
US Deputy Secretary of State John Sullivan will lead the delegation that will include Trump's daughter Ivanka, her husband and senior White House aide Jared Kushner, and Treasury Secretary Steven Mnuchin.
The US decision to move the embassy and to recognize Jerusalem as Israel's capital raised concern in many capitals, and outrage in some, that Washington is pre-judging the result of the Israeli-Palestinian conflict.
Trump has been criticized for handing his ally Prime Minister Benjamin Netanyahu a political victory without insisting on any Israeli concessions that might mollify Palestinians and help revive the moribund peace process.
But Friedman insisted that the embassy decision had been taken purely in the US national interest.
"The Israelis are obviously desirous of this, and they've requested this, and they're very happy by it," he said.
"But the decision was made because it was viewed to be in the best interests of the United States and something the president had promised during the campaign, and something the United States felt was in its best interests."