Hey All! So totally new to this fandom, but I watched the first episode and instantly shipped Starco. So I thought I'd do a little oneshot on how our favorite princess deals with jealousy. Enjoy~

Star Butterfly was the definition of sunshine and rainbows. She was the creation of all light and all happiness. She was able to shake anything off, turn any negative emotion into a positive one in the drop of a hat. So...why couldn't she shake the unbearable sadness that seemed to be clouding her very existence?

"Oh Marco..."She sighed, laying flat on her back and staring holes into her bedroom ceiling.

*FLASHBACK*

Star grinned, as she stood in front of the coffee table in the living room. On said table, was a bunch of junk foods that they both shared a love for, scattered with great care across the dark wooden surface.

"This is going to be the best Best friend Thursday ever!" She huffed triumphantly, moving to the couch where the snuggie they shared lay peacefully. Blue eyes glanced to the clock, Marco should be home at any moment.

All of a sudden, Marco burst into the house, a wide grin stretched over his handsome face.

"STAR STAR STAR!"

"MARCO MARCO MARCO!" She giggled slightly, raising a brow as the usually calm boy stood before her, rocking on the balls of his feet.

"What's got you all smiley and bouncy, best friend?"

"I finally did it! I finally worked up the courage and I asked out Jackie Lynn Thomas! She said yes! We have a date tonight!" He grinned, eyes scanning her face for the show of obvious joy he knew she would feel for him. Star seemed to freeze, eyes wide and mouth slowly agape. Marco smiled, completely oblivious to her mood, as he walked right passed her and bounded the steps leading to his room.

"I know I'm so excited! I gotta get ready!" The door to his roomed slammed, leaving Star alone in the suddenly extremely lonely living room. Before she had even any time to think, he came bouncing back down.

"So? How do I look?" He grinned at her, his eyes seemingly glazed over. Star stared at him for a while, taking in his appearance. He was dressed in black skinny jeans and a nicer version of his signature red hoodie. She smiled weakly, and nodded her head.

"Y-you look...you look good Marco."

Marco frowned, taking the time to look over to Star. His gaze shifted from her to the loaded table behind her. He stood, puzzled for a few moments, before it finally clicked. His brown eyes widened to the size of saucers.

"O-oh my god...it's Thursday...I...Oh Star I'm so-"

"No Marco. It's okay really. I mean you finally scored a date with your crush. Go for it."

"A-are you sure? I-I can always cancel and-" Star smiled, placing her hands on his shoulders and gave him a firm shake.

"None of that. Go. Have fun on your date, when you get home we can have our best friend Thursday okay? And you can tell me all about it."

Brown eyes scanned over Blue. Marco slowly smiled, gathering the smaller blonde in his arms in a tight hug.

"Thank you so much Star. You're the best!" He slowly let go, kissed her on the forehead and walked out the door, gently waving to her before closing the door and walking away. Star's smile slipped completely off her face, as a few tears managed to run their way down the weakly glowing hearts on her cheeks. It was then she knew things were changing, and not for the better.

*END FLASHBACK*

Star sighed, rolling on her left side. Her fingers traced the patterns of her cloud-design bed sheet as she let out a small whimper.

That moment was a month ago.

Marco and Jackie have been dating for an entire month.

Star tired to show her support for him in the beginning, hanging out with them and their group of friends, but things just weren't the same. Marco wouldn't talk to her like they used to. He wouldn't send her those small smiles, or stare at her in concern when something was wrong. It was like she was invisible to him, her best friend. Star hated the fact that they've drifted so far apart. She wanted to talk to him again.

Suddenly, an urge of determination pulsed through her like a heartbeat. Star stood up swiftly, walking over to her door and yanking it open.

"I'm gunna tell him. Im gunna tell him exactly how I feel, even though it's obvious he diesn't feel the same way about me."

She made her way down the hall and straight to his room, where without hesitation, pulled open the door and burst in.

"MARCO DIAZ IM IN LOVE WITH YOU!"

Star squeezed her eyes shut, waiting for a response.

1 minute went by...then 3...then 5...

Slowly opening her eyes, Star glanced around the slightly messy room.

It was empty.

"Oh wow...that's embarrassing...well maybe that was for the best... I don't think he would have reacted very well if he was here..." She laughed weakly, strolling into her best friend's room and taking a seat on his bed. She looked around and smiled, taking in the sights of all the karate posters hanging loosely on the wall. There were clothes, probably clean and dirty, scattered across the floor. The blonde haired beauty caught sight of his red hoodie on the floor.

"Huh...he never leaves home without this..."She mumbled, scooping up the hoodie and slipping it over her head. Taking a glance in the mirror, her hearted cheeks seemed to glow more than they ever had.

"Hehehe...I guess it kinda looks good on me..." She turned around slowly and examined herself in the mirror.

"Im Marco Diaz! People say I'm a Safe-Kid but really I'm some sort of misunderstood bad boy! I'm really kind and sweet and brave...I can do amazing karate and make the best nachos ever known to existance..I'm always there for my friends when they need it and I'm...so oblivous to my best friend Star's romantic feelings towards me..."

Star stared down at her hands, tears welling up in her eyes again.

"A-and I'll never know that...because Star won't ever say anything about that...I'm happy with Jackie Lynn Thomas...the prettier, more down to earth girl...that Star could...w-would never compare to..."

Star sniffled, more tears pouring down her cheeks. She grasped her chest tight, a small whimper escaped her lips. She slowly stood up, turning around to walk back to her room when she bumped into something warm.

"…..Star...?"