DeGeneres jokingly gave Theroux the doll so that The "Leftovers" star would not get lonely on the talk show while Aniston is away on set working, reported Us magazine.
"Oh, I know, I love him," Theroux joked in Aniston's voice while making the doll stroke his face.
The 44-year-old gushed that he loves being able to call Aniston, 46, his "wife" now.
"The first couple days of doing it, it's a great feeling. 'Fiancwe', after a while, sounds cute at first... Then, you get to say, 'My wife'," he said.