Selena Gomez and Justin Bieber sparked rumors of an engagement when Gomez was spotted wearing a diamond ring on her engagement finger on Wednesday.
Gomez's rep denied that Bieber had proposed to his 19-year-old girlfriend, telling Us Weekly, "She is not engaged."
The couple is currently in Cabo San Lucas, Mexico for the wedding of costume designer Shannon Larossi, who she met on the set of "Wizards of Waverly Place." According to TMZ, Gomez is a bridesmaid in the wedding party and plans to sing for the occasion.
The couple has been romantically linked since December 2010, but didn't confirm a relationship until May. Some of Bieber's fans, most of which are female, have referenced Gomez in threatening messages on Twitter and other social networking websites.
The young pop stars might not be ready to tie the knot just yet, but Bieber, 17, told Women's Wear Daily magazine that he would like to be married by the time he is 25-years-old.
"Well, by 25 or 26, I want to see myself, like, married or start looking for a family," Bieber told the trade magazine. "I want to be a young dad. I want to be able to have done what I wanted to do -- to be successful, to do a movie or whatever. But if the time is right, I definitely want to be married by 25. One thing -- I'm not looking to get married now."