Aniston has never publicly addressed her relationship with Vaughn that began while the co-stars were in Chicago filming "The Break-Up," TMZ.com noted.
However, in response to Winfrey's question, "Are you broken up?" Aniston responded, "Oh no, no."
On the same day, Vaughn issued a statement from London threatening to sue U.S. and London tabloids for reporting he had cheated on Aniston with a mystery woman.
"Ms. Aniston and Mr. Vaughn had not ended their relationship either at the material time or since," the statement from Vaughn said, adding reports of him passionately embracing a "mystery woman" were false.
Aniston also told Winfrey she had not surgically enhanced her bust, but admitted to gaining 10 pounds with a "couple cheese plates too many."