Crown Princess Mary's four appearances in her burgundy velvet Birgit Hallstein gown. By planning ahead with extra fabric, they were able to drastically alter it from a maternity gown to its current state, according to the designer.Mary had a birthday this week! She turned 42, and that requires a celebration. I prefer to celebrate with tiaras and gowns, how about you? (She's been out and about this past week, but nothing birthday worthy, I say.) I compiled a list of my favorite Mary outfits when she turned 40 and would certainly have more to add by now, but this is a classic favorite. There's a sort of medieval feel to the original maternity gown (worn twice while pregnant with Princess Isabella) that I just find delectable, and the gown's debut featuring the full necklace and earrings from the ruby parure with the tiara as Queen Ingrid wore it will always be one of my favorite royal gala appearances. I'm not as much a fan of the current version, but I love that it shows the evolution of her style - planning ahead since maternity wear has limited use, and reflecting the new flexibility of the ruby set that she's so clearly enjoying. Either way, regal as can be, and totally birthday worthy.