Just last year, Catholics were required to attend separate Masses two days in a row for the Sunday obligation and Monday's Christmas Mass. Now, they have a similar opportunity this year with the feast of the Immaculate Conception falling on a Saturday -- Dec. 8.

The vigil Mass on Saturday evening is not a "two-for-one" Mass for both days.

Last year, the U.S. bishops gave Catholics a heads-up about the back-to-back Sunday and Christmas liturgies 10 months in advance in a newsletter issued by the U.S. Conference of Catholic Bishops' Committee on Divine Worship. It also referenced what would occur this year and will recur when Dec. 8 falls on a Monday.

The newsletter specifically noted that the Saturday vigil does not count for both the holy day and Sunday in the very rare circumstances when two of the church's six holy days of obligation -- the feast of the Immaculate Conception or Christmas -- fall the day before or after Sunday.

"When consecutive obligations occur on Saturday-Sunday or Sunday-Monday, the faithful must attend Mass twice to fulfill two separate obligations," the committee said.

There is dispensation from a holy day Mass obligation when other holy days fall on Saturdays or Mondays but this does not apply to Christmas or the feast of the Immaculate Conception.

The U.S. bishops voted in 1991 to lift the obligation to attend Mass on holy days of obligation that fall on Saturdays or Mondays for three of the six holy days: the feast of Mary, Mother of God, Jan. 1; the feast of the Assumption, Aug. 15; and the feast of All Saints, Nov. 1.

Most dioceses have transferred observance of the feast of the Ascension from the Thursday 40 days after Easter to the following Sunday.

The bishops' committee has looked ahead to when these consecutive liturgies will happen again. In the next 12 years, Christmas will fall either on a Saturday or a Monday four times and the feast of the Immaculate Conception will fall on either of those days three times, including this year.

The Dec. 8 feast day has a long history in the United States. The U.S. bishops commended the nation to the patronage of Mary under the title of the Immaculate Conception in 1846. Pope Pius IX approved their decision Feb. 7, 1847. Eight years later, the pope declared the Immaculate Conception of Mary, that she was conceived without original sin, to be an article of faith. It became a holy day in the U.S. in 1885.

The feast was celebrated in some monasteries before the beginning of the eighth century and became more widespread in the 18th century.

The divine worship committee's newsletter emphasized the benefit of going to Mass on holy days even when they occur before or after a Sunday, stressing: "It would be hoped, of course, that Catholics foster a love for the sacred liturgy and hold a desire to celebrate the holy days as fully as is reasonably possible."

Or as one person responded on Twitter to this reporter's announcement about the Dec. 8 obligatory Mass attendance on Saturday: "That's correct! Daily Mass can be rewarding."