The Scotland Under-21 striker agreed to move to the Belgian side until the end of the season and has scored seven goals in his last five matches.
Lierse have since stated that they are eager to sign Watt on a permanent contract. The forward expects to discuss his future with Celtic and has admitted that he is content in Belgium.
"I will have to sit around the table with Celtic and wait to see what is decided," said Watt. "But I love Lierse and Belgium. We seem to be getting better with each passing week."