The most common and most likely answer to this crossword clue is the 7 letter word ORPHEUS
I've seen this crossword clue in Independent
O
R
P
H
E
U
S
More clues leading to the result ORPHEUS
- Classical musician to press hard for making a comeback
- Her opus excited legendary musician
- Legendary musician: King and he appearing separately in musical work
- Legendary musician‘s old Rush EP is warped
- Sup with Hero disguised as musician
- New opus here curtailed for classical musician
- Underworld figure turning up to take action against hospital professional
- He lost his wife taking her up, so awfully
- Dead person’s content to welcome the man at edge of Underworld — such as me?
- Mythical musician’s playing. Oh super!
Buddy explains!

The straight part
We know that "classical musician" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case classical musician = orpheus.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.