The 22-year old Guinea-Bissau-born Portugal youth international says his agent has been contacted by the Hoops and admits he would be open to the possibility of a move to Glasgow.
"If a deal is reached where I end up playing for Celtic, the fans will be asking themselves after a just a few games, 'Gary who'?
"I think I could go on and be the best striker in Scotland - and one of the best in Europe. Celtic will obviously be playing in Europe again next season and that's a big thing for me.
"I know they have been watching me for some time - with teams in England and Spain as well - but the important thing to me is that I sign for a team who are playing Champions League football because that is the level I believe I should be playing at."