Washington (CNN) - President Barack Obama and former Secretary of State Hillary Clinton had an "informal, private" lunch together Thursday, according to a White House official.
The lunch was not on Obama's public schedule and only became public when People Magazine tweeted a photo of a Sandra Westfall, the magazine's Washington bureau chief, with Clinton that suggested the former first lady was having lunch with Obama.
When other reporters picked up on the photo, noting that an Obama-Clinton lunch was not on the White House's schedule, People Magazine deleted the tweet until the White House confirmed the lunch.
"The President enjoyed an informal, private lunch with Secretary Clinton at the White House this afternoon," a White House official said.
The tweet has since been reposted.
A Clinton spokesman declined to give a statement and said that they would defer to the White House on the meeting.
The White House press corps was not notified of the lunch, causing Thursday's pool reporter to lodge a complaint with White House Press Secretary Jay Carney about the "lack of transparency."
Obama and Clinton were onetime rivals who faced off in the contentious Democratic presidential primary in 2008. After the contest, however, Clinton accepted Obama's offer to serve as secretary of state.
In recently released excerpts from her forthcoming memoir, Clinton called her teaming up with Obama "unexpected."
Since leaving the post in 2013, the former first lady has been mulling a run at the White House in 2016 and finds herself as her party's prohibitive favorite for the job.
That last time (that we know) Clinton and Obama had lunch at the White House was on July 28, 2013. That meeting was on Obama's public schedule, unlike Thursday's.
The two have, however, met at a number of high profile events since then. Earlier this month, at the dedication of the 9/11 museum, Barack and Michelle Obama toured the museum with Bill and Hillary Clinton.