"I have no idea," Jon told a group of paparazzi and fans in response to a question about where Kate was during an impromptu press conference and autograph signing outside his family's home on Father's Day, Us Weekly reported Sunday.
Jon conducted the unexpected session after a group of teenage girls stopped in front of the family's Wernersville, PA home and shouted "Happy Father's Day Jon!" after spotting him spending his Sunday afternoon watching the couple's eight children -- Cara, Mady, Aaden, Alexis, Collin, Hannah, Joel, and Leah -- as they played in the front yard, according to People.
After waving and shouting "Thank you" back at them, Jon then reportedly grabbed some publicity photos of the family and went down to the 24-acre property's front gate, where he autographed pictures for the girls, as well as additional passersby who also began stopping.
During the session, Jon declined to answer additional paparazzi questions about what tonight's heavily-hyped Jon & Kate Plus 8"big announcement" will be or whether he will still be living in the family's recently-purchased $1.1 million home after the announcement is made, according to video footage released by Splash News.
"You'll have to watch," Jon told a paparazzi repeatedly.
"That's all I'm going to say," he added with a laugh. "No hints."
However Jon did use the appearance to deny previous reports that he has been living in an apartment over the property's three-car garage.
"No, no," he said. "I live in the house with the kids."
Jon also told the group he hasn't been spending as much time with Deanna Hummel -- the 23-year-old "female friend" he allegedly had been having an affair with -- lately.
"Not as much," he said before adding that he had "learned my lesson" and stopped visiting local nightclubs. "Not with the things that went down."
"Dozens of people" ended up stopping by before the session ended, Us reported.
Kate was not home all weekend and had left the house early Friday morning before Jon returned from his recent apartment-hunting trip to New York City, according to People.
Last week, TLC announced that Jon and Kate will be revealing some "life-changing decisions" during tonight's special 9PM ET/PT one-hour broadcast their Jon & Kate Plus 8 reality show.
"Recently we've made some life-changing decisions. Decisions that will affect every member of our family. Ones that we hope will bring each of us some peace," Kate said during the voiceover of a 30-second version of new promotional commercials the network began running Wednesday night.
"Jon & Kate have an announcement." the network stated in on-screen text as Kate's voiceover and background music aired over video footage which showed Jon and Kate maintaining their distance during recent family activities.
"Monday, a one-hour Jon & Kate Plus 8 special. A family in turmoil. A relationship at a crossroads. Where do they go from here?" TLC stated in additional text that slowly flashed on-screen and faded throughout the 30-second commercial.