To some degree, the Buick Avenir was quite the surprise at the 2015 North American International Auto Show. It stole the show in terms of what General Motors offered up, and aside from the Ford GT, its easily one of the best reveals in terms of keeping a secret from the press. Buick held an extravagant party where it also unveiled the 2016 Buick Casacada convertible for North America, set to arrive early next year. We had a hunch Buick wouldn’t go through all that trouble just to show as an Opel we already knew was on the way, though. Shortly after, Mark Reuss took center stage and introduced what previews future Buick design. Thanks to a surprise performance by The Sing Off finalists, Ten (an accapella group), the Buick Avenir was unveiled to a harmony of music as it rolled out center stage. The design was assembled by Holden, where we can see future global ties forming between Buick, Opel and the Aussie brand. In addition, the Avenir concept could preview an all-new full-size sedan from Buick based on the all-new Omega RWD-based architecture. Have a look at the official unveiling video, which we’ve provided for you below.