Exsultate, jubilate. Rejoice, be glad. That's the name of Mozart's 1773 motet for soprano, orchestra, horns and organ that will serve as the interlude when Prince Andrew and Sarah Ferguson sign the wedding register in Westminster Abbey this week. It could also describe the response of lyric soprano Arleen Augér, 43, when she learned that she had been chosen to sing it. The exposure is expected to be a kick in the career for the California-born artist Augér (pronounced Oh-zhay). Her performances have earned her raves in Europe but until recently only a limited following on this side of the Atlantic, and she sees it as a long-awaited chance to "get more recognition from the man on the street." With an anticipated TV audience of 300 million, the royal marriage is without doubt the biggest date of Augér's 19-year career.

The choice of an American for such a plum assignment—even one whose father is Canadian and whose mother is of English descent—caused some curled lips in Britain's musical/political establishment. Such benefits, critics said, should rightly go to British, or at least Commonwealth, artists. With characteristic diplomacy, wedding organizers then added a second singer to the program; British soprano Felicity Lott will sing Mozart's Laudate Dominum.

The ruckus was news to Augér. A student of bel canto tenor Ralph Errolle and former member of the Vienna State Opera, she admits she had no idea how her selection came about. Unlike New Zealand soprano Kiri Te Kanawa, whom Prince Charles greatly admired and requested to sing at his and Princess Diana's 1981 nuptials, Augér is not thought to be one of the happy couple's favorites. Neither Andy nor Fergie is known for refined musical taste, theirs running more toward the Stones, Springsteen, Elton John and disco. The musical details for the wedding were thus left to Westminster Abbey organist and director of music Simon Preston.

According to the Rev. Alan Luff, precentor and sacrist at the Abbey, Preston, in consultation with the bride and groom, "first fixed the repertoire, then had to cast it. He wanted the best, and she is the best."

Augér doesn't give a hoot how it happened. "It's a great honor for me," she says, "and for an American."