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Mitt Romney may have quite the high-profile guest at his Jerusalem fundraiser. A donor to Romney who helped plan the presumptive GOP nominee's trip to Israel tells ABC News that Sheldon Adelson will be at his home in Israel and may stop by.

Adelson's spokesperson Ron Reese tells ABC News they won't comment his travel schedule, but did point out that the Las Vegas Sands is reporting its quarterly earnings today, meaning Adelson is in Las Vegas.

The donor is close friends with both Romney and Adelson. Adelson and his wife, Miriam-who is from Israel- have given at least $10 million to the pro-Romney superPAC Restore Our Future. They also gave $20 million to a superPAC supporting Newt Gingrich during the primary campaign. He has vowed to spend $100 million to defeat President Obama.

The fundraiser was supposed to be on Sunday night, July 29, after th e Jewish holiday of Tish a B'av, a day of fasting and mourning in Judaism and the saddest on the Jewish calendar. It has now been moved to Monday at 7:45 a.m. at the King David Hotel.

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The famous hotel located in the center of Jerusalem is walking distance from the Western Wall. The event will be small, with only about 20 to 30 attendees, and it is expected to last until 10 a.m., according to the donor planning the breakfast. The price tag is $50,000 per couple or $100, 000 raised. Only American citizens can donate to campaigns and most of the attendees will be Americans living in Israel or visiting at the time.

Romney is currently in London, but is expected to land in Israel Saturday night, give a major foreign policy speech on Sunday in Jerusalem, as well as meet with Prime Minister Benjamin Netanyahu, whom he's known since the 1970s when they worked together at the Boston Consulting Group. They are expected to dine together Sunday evening. Romney will also meet with President Shimon Peres, Palestinian Prime Minister Salam Fayyad, and U.S. Ambassador to Israel Daniel Shapiro.

The New York Times reported Monday that Adelson is behind the Republican Jewish Coalition's new multi-million dollar advertising blitz targeting Jewish voters in Florida, Ohio and Pennsylvania.

An earlier version of this story said Adelson was already in Israel, but he is still in Las Vegas as of Wednesday.