The Beverly Hills gathering scheduled for March 18 was called off because of a scheduling conflict, White House press secretary Stephanie Grisham told Politico.
The move comes amid concerns over large gatherings as the coronavirus outbreak continues to spike globally.
A three-day "Women for Trump" bus tour that was supposed to begin Monday was also canceled because of scheduling conflicts, according to a Trump campaign spokeswoman.
However, sources told the New York Times that the cancellation was because of the virus, which the campaign denied.
California Gov. Gavin Newsom declared a state of emergency last week. The state has more than 50 confirmed coronavirus cases and two deaths linked to the illness.
Washington lawmakers are now dealing with the impacts of the illness. Several members of Congress -- Sen. Ted Cruz, R-Texas, among them -- announced they were self-quarantining themselves after coming into contact with a person who tested positive for COVID-19 during last month's Conservative Political Action Conference in Maryland.
The first lady is also scheduled to host a March 25 fundraiser at Mar-a-Lago resort in Florida. It was unclear if that event is still slated to happen.