It's not over, Aniston tells Oprah

While taping a forthcoming episode of The Oprah Winfrey Show on Wednesday, Jennifer Aniston reportedly indicated that, contrary to rumors, she has not broken up with Vince Vaughn.

Several members from the audience of the show confirmed to PEOPLE that Anniston and Vaughn are "still on" and Aniston, 37, maintains that she and Vaughn, 36, have neither split, nor are they engaged.

Aniston appeared on the Show to promote the short film, Room 10, that she co-directed as part of Glamour magazine's "Reel Moments" series. The film is based on the real story of a nurse who gains perspective on her marital problems while caring for a dying patient.

"(Aniston) made it clear that she and Vaughn (were) 'still on'," said audience member Suzanne Hartigan.

Aniston reportedly wore a black tiered skirt and tank top for the filming and, according to audience member Margaret Stent, Aniston also said she had not had her breasts enlarged, explaining that when she gained weight, it went to her chest.

Aniston rolled her eyes when asked about Vaughn, added Stent.

American publication Us Weekly had reported late last week that the couple, who met while filming The Break-Up, had split after Vaughn called a halt to their relationship in an emotional phone call at the beginning of September - before he left to film his latest movie Joe Claus in London.

Later, Vince Vaughn was spotted in London with a mystery blonde at less than social distances suggesting that his relationship with Aniston was indeed over.