The Try Again hitmaker died in a plane crash in the Bahamas on 25 August, 2001, when she was just 22 years old.
Fans took to Twitter.com on Wednesday (16Jan13) to mark her birthday, and made 'Aaliyah' one of the top trending topics on the social networking site.
Elliott, who regularly collaborated with Aaliyah throughout the singer's short career, posted a special message for her pal on Twitter, writing, "We miss u (you) Aaliyah! It's not a day go pass (sic) we don't think of u and how your music still have a impact (sic) on the world! Rip baby girl."
Timbaland shared a link to the music video for Aaliyah's track 4 Page Letter, and re-tweeted the tribute, "Happy Birthday to the beautiful Aaliyah! Our angel... Never forgotten!"