The most common and most likely answer to this crossword clue is the 2 letter word ON
I've seen this crossword clue in The Daily Telegraph
O
N
More clues leading to the result ON
- So some prisoners released; just what pub needs
- Heading in the right direction about raising sheep and grass
- Both cricket sides constantly interrupted
- Like some performances for men only — I will stay outside
- Switch positions from time to time
- Acceptable rally in action in square?
- Where celebs are frequently working blind
- Tangoes wildly in front of the audience
- Openingin unit in factory, perhaps
- Occasionally working with old fellows
Buddy explains!

The straight part
We know that "in front of the audience" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in front of the audience = on.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 ON mean?
ON verb- To switch on
- In the state of being active, functioning or operating.
- Performing according to schedule; taking place.
- Fitted; covering; being worn.
- (usually negative) Acceptable, appropriate.
- Destined, normally in the context of a challenge being accepted; involved, doomed.
- Having reached a base as a runner and being positioned there, awaiting further action from a subsequent batter.
- Within the half of the field on the same side as the batsman's legs; the left side for a right-handed batsman.
- Menstruating.
- To an operating state.
- So as to cover or be fitted.
- Along, forwards (continuing an action).
- In continuation, at length.
- (obsolete in the US) Later.
- Of betting odds, denoting a better-than-even chance. See also odds-on.
- Positioned at the upper surface of, touching from above.
- Positioned at or resting against the outer surface of; attached to.
- Expressing figurative placement or attachment.
- Denoting performance or action by contact with the surface, upper part, or outside of anything; hence, by means of; with.
- At or in (a certain region or location).
- Near; adjacent to; alongside.
- Supported by (the specified part of itself).
- So as to impart force to.
- So as to impact; against.
- Covering.
- (with certain modes of transport, especially public transport) Inside (a vehicle) for the purpose of travelling.
- At the date of.
- Some time during the day of.
- At a given time after the start of something; at.
- Dealing with the subject of; about; concerning.
- In the possession of.
- Because of, or due to.
- Upon; at the time of (and often because of).
- Paid for by.
- Indicating a means or medium.
- Indicating the target of, or thing affected by, an event or action.
- Toward; for; indicating the object of an emotion.
- Indicating a means of subsistence.
- Away or occupied with (e.g. a scheduled activity).
- Regularly taking (a drug).
- Under the influence of (a drug).
- Having identical domain and codomain.
- Having V^n as domain and V as codomain, for some set V and integer n.
- Generated by.
- In addition to; besides; indicating multiplication or succession in a series.
- Of
- Indicating dependence or reliance; with confidence in.
- At the peril of, or for the safety of.
- In the service of; connected with; of the number of.
- By virtue of; with the pledge of.
- To the account or detriment of; denoting imprecation or invocation, or coming to, falling, or resting upon.
- (especially when numbers of combatants or competitors are specified) Against; in opposition to.
- Without.
- In the Japanese language, a pronunciation, or reading, of a kanji character that was originally based on the character's pronunciation in Chinese, contrasted with kun.