On the CBS sitcom, future Ted (Bob Saget) revealed that his past self (Radnor) will soon break up with his latest love interest (Jennifer Morrison).
"They have their problems, it seems," Radnor told Give Me My Remote. "I think they really dig each other but they're a little [argumentative] with each other."
He added: "It's always been an incredibly passionate relationship and sometimes that passion spills over into screaming matches."
The actor also suggested that the early reveal of Ted and Zoey's break-up could be a "fake out".
"It doesn't seem like it ends well, [but] we don't know," he hinted. "Is Ted a reliable narrator?"
The show's co-creator Craig Thomas previously described the couple as "highly flammable" and claimed that knowledge of their future "whets one's appetite to see a truly grand train wreck of an ending".
How I Met Your Mother currently airs on Mondays at 8/7c on CBS.
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