Selena Gomez ran away from Jennifer Aniston because she was so star-struck.

The 'Spring Breakers' actress was so "terrified" when she met the 'Friends' star -- who is one of her acting idols -- she walked away from her and admits that the awkward encounter is one of the most embarrassing moments of her life.

In an interview with Radio Disney, she explained: "I ran away from Jennifer Aniston when she said, 'Hi.' I was terrified of her. I was scared, so I ran away and I'm really embarrassed about that."

The 20-year-old beauty blamed her strange behaviour on watching Jennifer in hit sitcom 'Friends', in which the 44-year-old actress played Rachel Green for 10 years.

She laughed: "I didn't know what to do -- it's Rachel!"

Meanwhile, Selena -- who split from 'Baby' singer Justin Bieber last year -- has insisted that her new single, 'Come and Get It', is not about her former boyfriend.

She said: "It's not really about a specific person ... It exudes confidence and strength and that is something I'm willing to share with the world ... I want to represent something good and be a good example."

The star also revealed to Ryan Seacrest on his radio show that she is planning a huge bash to celebrate her 21st birthday in July.

She added: "I'm gonna have a big party. It's gonna end up at my house. I wanted to do like a hip-hop theme."