Diandra is caught off guard on Wednesday's So Cosmo episode when she learns that her former crush Evan is going rock climbing with her good friend Tiffany.
"Why didn't you guys tell me you were going rock climbing?" Diandra asks Tiffany and Evan in the clip above.
"Oh, I didn't think about it," Tiffany says. "You weren't around when we were making the plan."
Diandra, clearly annoyed by the situation, tells the duo, "OK, well have fun rock climbing."
When Tiffany sees Diandra's reaction, she tells her to "calm down."
"I'm calm!" Diandra replies.
Tiffany then tells Evan, "Let's go, she's being a brat."
Take a look at the So Cosmo clip above to see Diandra react to Evan and Tiffany growing closer!