Kevin Przytula, 33, popped the question to longtime girlfriend Allyssa Anter, 27, on Saturday in Bay City, Michigan.
The moment was captured on camera by family.
The groom-to-be Kevin Przytula, from Michigan, US, had wanted to make sure his girlfriend's son Owen was there when he asked for her hand in marriage, so he got down on one knee when they were stood by a water fountain in Bay City.
They were alerted to the pint-sized proposal crasher by the giggling videographer, Przytula's 11-year-old daughter, Kayleigh.
Little Owen drops his trousers simply as his dad drops down on one kneeconfer with caption.More news: Tom Cruise's Mission Impossible: Fallout unveils chaotic new poster, announces release date
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"I just started laughing, this is what Owen does", Allyssa said. However, the man recording the proposal couldn't hold back his laughter any longer as Owen took a leak. Do you've got a narrative for The Solar On-line information crew?
"Oh my God. You guys?" the friend said through laughs.
Speaking to the Bay City Times, Allyssa said they were working on potty training the toddler and saw the amusing side of the proposal hijacking.
'He pees outside at home sometimes in the yard, and we went and got ice cream the other day and he did it in the parking lot there.
"He just does it without telling anybody, he just pulls his trousers down and goes".