The 19-year-old signs from Maccabi Petah Tikva in a deal brokered by well-known agent Dudu Dahan.
The winger has already played over 60 games for his former club, racking up 20 goals and 10 assists at such a young age.
Liel does predominantly play on the right hand side but can also play up front if needed.
He becomes the third new signing this summer after Liam Shaw and Osaze Uroghide who both came in on a free from Sheffield Wednesday.
He will likely contest the right wing with James Forrest. Celtic were left very short in that area last season when James suffered a season-ending in jury early on in the season during a Champions League qualifier. Having more depth and youth in the position is a big positive.
This signing must mean the end for Marian Shved’s time at Celtic, the winger has not returned to Celtic in pre-season and there’s been no sign Celtic are going to use him.