Miku is on a season-long loan from La Liga outfit Getafe, but has thus far underwhelmed during his time in Scotland, scoring only once in 10 games, and it is believed that he may not see out the duration of the deal.
Rumours also began to surface that he and his family were unsettled in Glasgow, but Lennon insists that the striker is happy at Celtic.
"We had a wee chat yesterday," Lennon told The Scotsman.
"He is happy here.
"He knows he can do better but he wants to stay and be a success and I am very happy with that."