What does the cryptic crossword clue "Illicitly, a romance being filmed (2,6)" mean?

The definition is "filmed". The wordplay uses an anagram. anagram of A + ROMANCE = ONCAMERA; definition: "being filmed" The answer is ONCAMERA.

Illicitly, a romance being filmed (2,6)

Guardian Cryptic #27619 | 17 Down | 2018-09-20 flower