Democratic presidential frontrunner Hillary Clinton met with President Barack Obama for an "informal lunch" Monday, the White House confirms.

The White House characterized the meeting as "mostly a social occasion."

"When their schedules permit, President Obama and Secretary Clinton enjoy the opportunity to catch-up in person," White House press secretary Josh Earnest said in a statement. "This afternoon they met privately for an informal lunch here at the White House for about an hour and a half. They discussed a wide array of topics, but this was mostly a social occasion."

The visit comes less than 24 hours after Obama addressed the nation about the fight against ISIS. Clinton has not yet commented publicly on Obama's remarks.

Obama and the First Lady are scheduled to attend an annual Congressional Ball at the White House on Monday night.

Clinton had no open events on her calendar today but she did have two fundraisers scheduled: one in Washington, DC and one in Owings Mills, MD.

NBC's Monica Alba contributed to this report.