The "Friends" actress told People magazine that reports of her engagement to the "Be Cool" actor, including an article in Us Weekly, are false, calling the stories "insane."
"I'm not engaged, and I don't have a ring, and I haven't been proposed to," Aniston told People, according to an article appearing on the magazine's Web site Wednesday.
Us Weekly reported in a recent cover story, citing anonymous sources, that Vaughn had proposed to Aniston on June 27 on a private jet after a trip to Mexico. Janice Min, the editor in chief of Us Weekly, appeared on the "Today" show Aug. 9 and told co-anchor Ann Curry, "This engagement happened more than six weeks ago ... Vince had the ring, he got down on one knee and proposed. And Jennifer said yes on the flight."
Us Weekly is sticking by its story, which other media outlets picked up.
"Us Weekly based its story on lengthy interviews with four separate and independent sources close to the couple, including two who learned of the engagement directly from Vince Vaughn," the magazine said in a statement Wednesday. "Jennifer's publicist never denied the engagement in advance of publication."
People magazine said Aniston, who has starred in such movies as "Along Came Polly" and "Bruce Almighty," called to clarify the reports.
Aniston said she normally ignores rumors published about her but wanted to speak this time because the reports had been picked up by mainstream news outlets.
"The only reason I'm saying something is because if we're listening to the news we're supposed to be believing in the news," she said.
Aniston was vague about her relationship with Vaughn, whom she met last year while filming "The Break-Up."
"We're just being," she told People. "We're having a good time."
Meanwhile, Us Weekly's new issue, which is currently on stands, talks of "Jen's 'I Do' Dreams." The magazine still says that the couple is engaged and plans to wed next year.
Us Weekly says that one reason the star may be keeping the engagement quiet (and not wearing the reported $500,000 diamond ring Vaughn gave her) is because, as one source says, "she will treat this wedding as if it is her first while keeping it low key. She is not going to let anyone ruin this."
The magazine also reported that Aniston's rep, Stephen Huvane, has a history of denying stories that later prove to be true, citing an instance in 1999 when Aniston was dating Brad Pitt and sported a ring on her ring finger at a Sting concert.
"Even though the sparkler was on the appropriate finger, Huvane told the media, 'It's not an engagement ring,' " the magazine reports in its new issue.
Additionally, the magazine says that Aniston's purported wedding to Vaughn will be "casual ... like a party," according to an unidentified source, and that her wedding dress will be simple and, of course, white.