In the 1979/1980 season of the European Cup, which was the predecessor of the Champions League, Nottingham Forest not only made it to the final but also won the whole thing without being a national champion the preceding season. Nottingham was qualified as winners of the 1978/79 European Cup, to which they in turn qualified as winners of the English top division 1977/78. (It wasn't called Premier League at that time.) I believe, but can't guarantee, that Nottingham Forest at the time was the only team to win the European Cup more times than the national championship.
Sep 19 2022, 8:05 AM
(Not claiming that the first answer was wrong, just adding a bit of interesting information about the predecessor of Champions League.)