In the recent season six finale, it emerged that Barney (Neil Patrick Harris) was getting married at the mysterious future wedding.
Thomas later confirmed that more details about the nuptials will be revealed when the show returns in the fall.
He has now told Entertainment Weekly that he wants to unveil more information slowly, but quickly enough to keep viewers interested.
"[That's] one of the big challenges of any long-running sitcom, especially one you watch in part for comfort because you know what you're going to get and you love these characters and you don't want them to change," he said. "As a showrunner, you don't want to be too repetitive either. You want to go new places with these characters."
Thomas added: "I think the way we have it set up for season seven, I think it'll be the best of both worlds. I don't want to say exactly what becomes of Barney in season seven, but you're going to get to see him in both Single Barney world and Couple Barney mode. But I won't say exactly with whom."
How I Met Your Mother, which has been renewed for two more seasons, will return in the fall on CBS.
> 'HIMYM' exec: 'Next season is blockbuster'