The 39-year-old couldn't prevent her ex-husband from attending the event at St. John's Church of Christ in Wernersville, Pa., over the weekend, but she did do her best to avoid him.
"[She] stayed clear away," an onlooker told Us Weekly. "If he would go anywhere near her, she'd keep her distance. She wouldn't get [close to] Jon because she knows that's what he wants, for those pictures to go everywhere."
Gosselin filmed the event for her upcoming "Kate Plus 8" television special, and donated part of the proceeds to the Animal Rescue League of Berks County. The reality star posed for several photographs with attendees, and the eyewitness said she appeared amiable when Jon showed up.
"She was on camera, so she was 'on,'" the onlooker related. "When she saw [Jon], she of course smiled. She's very animated with her facial expressions. She's not a stoic person."
The Gosselins came to fame on TLC series "Jon & Kate Plus 8" in 2007. The reality show followed the couple's daily lives with their eight children, and the title was changed to "Kate Plus 8" after their divorce in 2009.
"Kate Plus 8" will return to television with new episodes in December.
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