The 46-year-old actor was scheduled to appear on Tuesday's episode of The Late Show; however, he is no longer listed as a guest. Kristen Gillibrand, Chris Gethard and Portugal. The Man are set to appear.
E! News has reached out to both Theroux's rep and The Late Show for comment.
Theroux and Aniston announced their separation in a joint statement last week.
"In an effort to reduce any further speculation, we have decided to announce our separation. This decision was mutual and lovingly made at the end of last year. We are two best friends who have decided to part ways as a couple, but look forward to continuing our cherished friendship," the couple said. "Normally we would do this privately, but given that the gossip industry cannot resist an opportunity to speculate and invent, we wanted to convey the truth directly. Whatever else is printed about us that is not directly from us, is someone else's fictional narrative. Above all, we are determined to maintain the deep respect and love that we have for one another."