The FAA ATP is technically an ICAO ATPL, as long as you meet the experience criteria per the ICAO. Is your TT 1500? with only 50% SIC time counting towards that number. And do you have 250 true hours as PIC? actual PIC, as in sole manipulator of the controls with knowbody else logging PIC at the same time in the aircraft. If yes to these questions, you have an ICAO ATP(L).
Cheers,
Cheers,