Madeline Denise McCarthy and Matthew Thorn Smith made their acting debuts in 2000 in a TV ad promoting the Yogi Berra Museum & Learning Center at Montclair State University in Little Falls, N.J.

Both were in first grade.

Mr. Smith had run circles around an upright baseball bat with his forehead on its knob, and got so dizzy he toppled over in the video, while she pretended to spit tobacco in the adjacent field.

“We were a few feet away from each other in the dugout between shots,” Mr. Smith, 32, said, which they only realized in college.

They were among about a dozen local children in vintage uniforms improvising baseball-related moves for a series of ads, and last Thanksgiving watched a digitized version of the one they were in with their families.

The two, who grew up about a mile from each other in Montclair, N.J., went to different schools until both ended up at Montclair High School, where they met in 2007 as sophomores in gym class.

Their friend circles often overlapped — especially on her parents’ front porch during lunch or weekends, thanks mostly to their older siblings. “She had a party house,” Mr. Smith said.