The most common and most likely answer to this crossword clue is the 12 letter word CROWD-PULLER
I've seen this crossword clue in The Guardian
C
R
O
W
D
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P
U
L
L
E
R
More clues leading to the result CROWD-PULLER
Buddy explains!
The straight part
We know that "popular event /popular event" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case popular event /popular event = crowd-puller.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CROWD-PULLER mean?
CROWD-PULLER noun- An event that attracts a large number of people.