It's so hard to say goodbye. Selena Gomez held yet another birthday celebration to ring in her big 2-1 with family and friends at Revolve Clothing beach house in Malibu on Saturday, July 27, with one famous (and unannounced) face making a late appearance: on-again, off-again boyfriend Justin Bieber.
The "Heartbreaker" singer, 19, arrived at the gypsy-themed house party around 9 p.m., an eyewitness tells Us, dressed down in a black-and-green letterman jacket, dark jeans and white high-tops, with a small present for the birthday girl.
"Justin flew in specifically for the party on a day off from his tour," the source tells Us. "He wasn't dressed in costume, but carried a single red rose in his hand."
Other celebrity guests included Julianne Hough, Nina Dobrev, Derek Hough, Ashley Benson and Jaden Smith, among others. Best friend Taylor Swift was performing at a show and unable to attend.
The Hollywood pals took shots of chilled VeeV when Gomez's birthday song came on, and noshed on Mediterranean food at the fun-filled bash.
"Everybody danced and had a blast, especially Selena, who was surrounded by her friends," an insider tells Us. Gomez's birthday cake was shaped like an elephant on a pillow, with a giant "21" sitting atop the creation, the source tells Us.
Gomez even had belly dancers, mermaids, snakes and henna tattoo artists at her themed soiree.
Later in the night, Smith helped the Gomez and Bieber sneak out of the house under a blanket and an umbrella, the source tells Us. Gomez and Bieber were holding hands.
Earlier this month, the "Come & Get It" singer cut an interview short after Chicago's WGN Entertainment host Dean Richards brought Bieber up in conversation.
"Is there something about him that we don't get or we don't understand?" Richards asked about Gomez's reported ex. "I mean, there's one story after the other of pretty outrageous things that we are reading about. What don't we get about him? Or what is it that he's not getting out there?"
Gomez let the awkward silence settle in as she rolled her eyes and glanced off-camera for support from her team. She laughed awkwardly before the interview cut to a black screen urging fans to buy tickets for her Stars Dance tour.