It's been reported that Psy announced news of his comeback at the '1theK Global Peace Manilla Concert 2017' in Manilla, the Philippines on March 2.
YG Entertainment backed up the news with, "Psy himself delivered the news of his comeback for this April during his performance in the Philippines. We know that production for his new album has been going on diligently since last year."
Psy's comeback in April will mean his first in a year and 4 months, since his 7th album. Can't wait for it!