There have been alot of rumors flying about lately regarding the religion of the next Princess of Monaco. Charlene was raised Protestant but, in an interview (which readers will have seen) she identified herself only as "Christian". The media had reported (in one of those off-hand type remarks the modern media is so good at, and frequently passes along incorrect information) that Charlene was taking catechism classes and would or had become Catholic. In the interview mentioned above, when asked about the subject of religion, Prince Albert II pointed out that, unlike Great Britain for example, there is freedom of religion for everyone in Monaco, including the spouse of the Sovereign Prince. Charlene does not have to be a Catholic to be the Princess of Monaco, though it would be the first time in the very long history of the country that such a thing happened.
So, now there is speculation about whether Charlene is or is not a Catholic or if she has or does not have any plans to change her religion. Charlene has attended mass with the Grimaldis, she crossed herself, genuflected to the Archbishop and so on. I don't know if she's taken communion, that is not usually shown anyway. Few would accuse the Grimaldis of being a devoutly religious family these days, but they do take religion seriously. Princess Stephanie, known for her 'wild ways' respectfully abstains from communion when that is called for and Prince Albert II has had very good relations with the Holy See throughout his reign. Now, whether Charlene is or is not a Catholic at this time I cannot say with 100% certainty. She has shown almost all the outward signs of being one and it would be my opinion that she is or is in the process of becoming one.
To be rather blunt, I don't think Charlene gives religious issues a great deal of attention. That is no slam against her, some people make it a priority and other people do not -it's just not a part of their lives. In an interview with her parents they made no issue out of the difference in religious upbringing between their daughter and her intended. Despite the fact that there is no law against it, I would be very, very surprised if Charlene remained even a nominal Protestant. It would be unprecedented in Monegasque history and I think would reflect poorly on her, given that she has not given the impression of specific church membership being that important to her, not to go along with the religion of her husband and the vast majority of the people of Monaco. To stress though, it is my opinion that she has become a Catholic or will shortly, perhaps at Easter time (which is when it usually happens but not always). If there is a public confirmation at Easter in preparation for the marriage it will certainly be known.