Dorries and the party's chief whip, Sir George Young, had what was described as a "pleasant" meeting, The Sun reported. Dorries, who had been sitting as an independent, was reinstated in the party and as one of the parliamentary whips.
"Nadine has apologized for absenting herself from her parliamentary duties without permission," a Conservative spokesman said.
Dorries, who represents a Bedfordshire district, was kicked out of the party after leaders learned she was to appear on "I'm a Celebrity: Get Me Out of Here," filming in Australia. During her time in the wilderness, there were rumors she might affiliate with the United Kingdom Independence Party.
Dorries called her reinstatement "long overdue" and said she would not be "shackled" by Conservative leaders. But she also struck a conciliatory note.
"It's nice to be back in the fold and a Conservative MP again," she said.