The most common and most likely answer to this crossword clue is the 6 letter word LENNON
L
E
N
N
O
N
More clues leading to the result LENNON
- Famous Liverpudlian flag, 50 for a penny
- At last, Liverpool home town given hero musician
- Singer that’s rejected Christmas — gripping news!
- ‘Woman’ writer? New name in Spanish region
- Pop star‘s names appearing in and around sign?
- Musical kings imprisoning knights yield legendary musician
- The French facing their vote against accepting new or old pop star
- Songwriter’s selection stolen? Nonsense
Buddy explains!

The straight part
We know that "old pop star" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old pop star = lennon.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.