Joseph Smith calls Jesus "Jehovah" in D&C 110.
Section 110:1-10, Doctrine and Covenants, The Church of Jesus Christ of Latter-Day Saints, accessed September 24, 2022
1 The veil was taken from our minds, and the eyes of our understanding were opened.
2 We saw the Lord standing upon the breastwork of the pulpit, before us; and under his feet was a paved work of pure gold, in color like amber.
3 His eyes were as a flame of fire; the hair of his head was white like the pure snow; his countenance shone above the brightness of the sun; and his voice was as the sound of the rushing of great waters, even the voice of Jehovah, saying:
4 I am the first and the last; I am he who liveth, I am he who was slain; I am your advocate with the Father.
5 Behold, your sins are forgiven you; you are clean before me; therefore, lift up your heads and rejoice.
6 Let the hearts of your brethren rejoice, and let the hearts of all my people rejoice, who have, with their might, built this house to my name.
7 For behold, I have accepted this house, and my name shall be here; and I will manifest myself to my people in mercy in this house.
8 Yea, I will appear unto my servants, and speak unto them with mine own voice, if my people will keep my commandments, and do not pollute this holy house.
9 Yea the hearts of thousands and tens of thousands shall greatly rejoice in consequence of the blessings which shall be poured out, and the endowment with which my servants have been endowed in this house.
10 And the fame of this house shall spread to foreign lands; and this is the beginning of the blessing which shall be poured out upon the heads of my people. Even so. Amen.