The most common and most likely answer to this crossword clue is the 7 letter word CONCERT
I've seen this crossword clue in The Daily Telegraph
C
O
N
C
E
R
T
More clues leading to the result CONCERT
Buddy explains!

The straight part
We know that "In this/and on stage!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in this/and on stage! = concert.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 CONCERT mean?
CONCERT noun- Agreement in a design or plan; union formed by mutual communication of opinions and views; accordance in a scheme; harmony; simultaneous action.
- Musical accordance or harmony; concord.
- A musical entertainment in which several voices or instruments take part.
- To plan together; to settle or adjust by conference, agreement, or consultation.
- To plan; to devise; to arrange.
- To act in harmony or conjunction; to form combined plans.