"I was reporter No. 15," he told TVGuide.com of his role in the film. "I was at the very end of the movie when Ben Affleck is sitting on the bed and I'm on the news recapping the entire story."
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The Bachelor host did not have scenes with Affleck or Paltrow, but plans to bring up his blink-and-you'll-miss-it appearance with the actress should they chat at the Grammy Awards red carpet on Sunday.
"I didn't realize in a Ben Affleck movie they're going to show Ben Affleck and not Chris Harrison," he says. "There's the scene and then behind Affleck, you see the reflection of me on the TV."
Besides sharing his funny story with the Country Strong star, Harrison is looking forward to interviewing folk from the music industry, which he finds "extremely fascinating."
"They are so unguarded and will say anything that's on their mind," he says. "These guys are like, 'I am who I am if you don't like it you can suck it.' It makes for a really fun red carpet."
Tune in to the Grammy Awards Red Carpet with Chris Harrison on Sunday at 6/5c on TV Guide Network.