Life Unexpected Life Unexpected

Despite the musical guests galore, Life Unexpected's Lux has one thing on her mind at the K100 festival — her crush, Eric. Unfortunately, getting his attention doesn't go as planned.

"I get dressed up and come to find out that he brought another date," Britt Robertson, who plays Lux, tells

Exclusive behind-the-scenes photos: Life Unexpected and One Tree Hill get musical

On Tuesday's Life Unexpected-One Tree Hill crossover (9/8c on CW), Cate, Ryan and Lux are joined by Tree Hill singing sensation, Mia Catalano, and her producer, Haley Scott. Coincidences abound when Cate and Haley realize they were both knocked up in high school by Nate and Nathan, respectively. With Haley pregnant, Cate and Ryan discuss — or rather, heatedly debate — whether they should give babies a try, too.

In the video below, Robertson talks about whether Eric (Shaun Sipos) will be around for long, and how the dynamic between Lux and Cate could change if a little one were on the way.