President Gordon B. Hinckley made the announcement on the first day of the faith's 174th Semi-Annual General Conference, restoring the Quorum to its full complement following the deaths of Neal A. Maxwell and David B. Haight in July.
Inviting Uchtdorf and Bednar to take their seats among the other apostles, Hinckley urged the audience to "get a good look at them," earning a big laugh from the 21,000 gathered in the Conference Center in downtown Salt Lake City.
And Hinckley paid tribute to Haight and Maxwell. "Each of them served long and well. We mourn their passing. . . . We are confident they are carrying on this great work on the other side of the veil."
Uchtdorf, 63, a former pilot and executive for Lufthansa German Airlines, has been serving as one of the Seven Presidents of Seventy, an LDS presiding quorum.
He is the first foreign-born apostle since Marion G. Romney, born to American parents in Colonia Juarez, Mexico, was ordained in 1951.
Bednar, 52, is president of Brigham Young University-Idaho and an Area Authority Seventy for the church. Both are to speak today during the closing sessions of The Church of Jesus Christ of Latter-day Saints' two-day conference. Later Saturday, church leaders explained the nature of the faith's Quorum of the Twelve.
Along with the three-man First Presidency, the 12 apostles "are commissioned by God and sustained by you as 'prophets, seers and revelators,' " Apostle Jeffrey R. Holland told the Conference Center audience as well as millions more listening around the world.
The president of the church, Holland said, is "the Prophet, Seer and Revelator, the senior Apostle, and as such the only man authorized to exercise all of the revelatory and administrative keys of the church."
The 15 men form the "foundation stones" of the church, Holland said, and "the chief cornerstone is Jesus Christ."
In a practical sense, the First Presidency and the apostles occupy the top tier of leadership and administration of the 12 million-member church. Together, they establish policies and programs, decide on new leadership callings and manage congregations.
Apostles also are sent around the world to tend to particular areas. For example, Dallin Oaks has spent much of the past two years in the Philippines; Holland has been in Chile; and last month L. Tom Perry arrived in Germany for a similar stint.
"A special brotherhood": Perry, back for conference, quoted the late Stephen L. Richards, a counselor in the First Presidency, as defining a quorum - the church has many throughout its lay clergy - as "three things: first, a class; second, a fraternity; and third, a service unit."
But on a personal level, Perry said, the Quorum is "a special brotherhood."
"We are there to lift, inspire and bless each other with the spirit of our calling," he said. "When one is burdened, there are 11 others anxious to help lift and share that burden."
In the morning session, Apostle Richard G. Scott offered his thoughts on the value of forgiveness, even when one has been seriously transgressed against.
To be forgiven of a violation "great or small," he said, the solution requires "full repentance through faith in Jesus Christ and his atonement with obedience to his commandments.
"When needed, full repentance will require action on your part," including confession, abandonment of sin, restitution, obedience and seeking forgiveness, Scott said.
Those who are innocent and have been seriously wronged should not "harbor feelings of hatred, anger at what appears to be unjust. Forgive the offender. . . . Such forgiveness is most difficult, but it is the sure path to peace and healing."
Priesthood meeting: During Saturday evening's priesthood meeting for boys and men, Hinckley railed against pornography, likening it to a "raging storm, destroying individuals and families, utterly ruining what was once wholesome and beautiful."
He said many wives had written to him, describing how their husbands had substituted pornography for righteous lives and marriages.
"Please warn the brethren [and sisters]," one woman wrote. "Pornography . . . has the effect of damaging hearts and souls to their very depths, strangling the life out of relationships that should be sacred, hurting to the very core those you should love the most."
"If there be any within the sound of my voice who are [seeking out pornography], then may you plead the Lord out of the depths of your soul that he will remove you from the addiction that enslaves you."
He added, "And to all of you, young or old, who are not involved, I congratulate you and leave my blessing with you."