Neeson says of Istanbul:
“The call to prayer happens five times a day and for the first week it drives you crazy, and then it just gets into your spirit and it’s the most beautiful, beautiful thing.
“There are 4,000 mosques in the city. Some are just stunning and it really makes me think about becoming a Muslim.”
He needs to think about this some more. There's nothing stopping him from praying regularly as a Catholic, which I gather he doesn't really practice. Catholicism is a far more intellectual religion than Islam, so Islam tends to suit those that have trouble with concepts such as The Trinity (three persons in one God) or the Incarnation (the Second Person of the Trinity becoming man). If he stays Catholic, no one is going to make him pray like the almost political nature of Islamic group prayer where if you are not there joining in, people will notice.
Hilaire Belloc said of the Islamic religion that "it was a perversion of Christian doctrine". That on the whole, Mohammad, a pagan who lived on the fringe of the Catholic world, absorbed Catholicism and simplified his own version of it. However, by denying the Incarnation, he went much further than the Arians of his time (Christians that denied Jesus was divine), and by doing so wiped out the whole sacramental system of Christianity, making Islam very different. See an old post of mine, The great and enduring heresy of Mohommad.
Belloc also predicted back in his time (the first half of the previous century) that Islam would return. In a time of massive Christian lukewarmness, it is any wonder that those such as Neeson are attracted to the enforced religiosity of Islam?
Related link: Liam Neeson says he is thinking of becoming a Muslim ~ Holy Post