Revelation 19:20 And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.

At the second advent, the beast and the false prophet are cast into the lake of fire.

Then a thousand years later:

Revelation 20:10 And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.

So during the thousand years, are the beast and the false prophet the only ones in the lake of fire?

If so, when are the worshippers of the beast cast in there?

Revelation 14:9 And the third angel followed them, saying with a loud voice, If any man worship the beast and his image, and receive his mark in his forehead, or in his hand,

  10 The same shall drink of the wine of the wrath of God, which is poured out without mixture into the cup of his indignation; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb:

  11 And the smoke of their torment ascendeth up for ever and ever: and they have no rest day nor night, who worship the beast and his image, and whosoever receiveth the mark of his name.

So will they be cast into the lake of fire at the great white throne judgment?

Revelation 20:14 And death and hell were cast into the lake of fire. This is the second death.

  15 And whosoever was not found written in the book of life was cast into the lake of fire.