Could be. I haven't seen anywhere where she's confirmed it, though. Here's the thing with "celebrity Pagans." I've noticed over the years that if a celebrity makes any reference at all to anything outside of the Mainstream Religions, they're automatically tagged as Pagan. For years, rumors have floated around about singer Stevie Nicks being Wiccan, despite the fact that she's never said she is. I think many of the rumors stem from the elaborate Pagan imagery in her videos. Likewise, a while back Cybill Shepherd made some acceptance speech in which she "thanked the Goddess," and people just went crazy over it -- is she Wiccan or isn't she? Or is she just someone who accepts the polarity of the Divine?
Honestly, it's none of my business.
A few years ago someone blogged a list of "Celebrity Pagans," and it was kind of silly, because it had everyone one it who wasn't Christian or Jewish. Richard Gere showed up on there, and he's said he's a Buddhist. I think Madonna was on that list, and she follows Kabbalah. It also had plenty of Young Hollywood people on there who are mostly just Goth-y types, but that doesn't make them Pagan.
Also, bear in mind that there's a need to set and follow trends in Hollywood. Remember when all of a sudden everyone had those little red Kabbalah bracelets on? Can you imagine the stampede if some A-lister like Angelina Jolie said she was a practicing Wiccan? Everyone would be sporting diamond-encrusted pentacle necklaces from Harry Winston.
To my knowledge, only a few celebrities have actually come out and said they are Pagan. Godsmack singer Sully Erna has been publicly Wiccan for a long time, and was recently initiated into the Cabot tradition. Actress Fairuza Balk owns (or did, for a while) an occult store in Los Angeles, although I'm not sure what flavor of Pagan she actually is. There are a couple of authors who have come out as being Pagans or Wiccans as well.
I think an important point to make is that just because someone is a celebrity doesn't necessarily mean they should be "outed" as far as their belief system goes. I would never out a fellow coven member, and likewise, I don't think any of us should be outing people we don't know personally, either. It's fine to speculate, but that's really all it should ever be. If some celebrity wants us to know what their belief system is, I'm sure their publicist will let the whole world know.