Selena Gomez is Blue and Other Celebrity Twitpics of the Week

Selena Gomez

This week, the star-studded world of Twitter revealed variations of Katy Perry's makeup from the new E.T. video, Jessica Simpson's and Michelle Trachtenberg's design pursuits, and Lady Gaga…in hell.

Katy Perry's E.T. makeup.

A fan imitates Katy Kerry's E.T. beauty look.

Pics from Katy Perry's upcoming video for the intense single "E.T." leaked, and fans are already copying her out-there beauty look, and posting their pictures on Twitter. "Sweet Cali Dreams! ;D I've been abducted," wrote one fan.

Selena Gomez in blue makeup for a Perez Hilton bash.Jessica Simpson tweeted an odd pic of blue flippers.

Katy Perry's not the only one inspired by aliens lately. Selena Gomez tweeted this pic of the futuristic blue makeup and body jewels which she wore to Perez Hilton's Blue Ball 33rd birthday party. In what we can only hope is a joke, Jessica Simpson posted a pic of blue flippers with stiletto heels, and tweeted, "Scuba gear coming soon for @jscollection heels for every occasion ;)"

Michelle Trachtenberg & Rebecca Taylor are collaborating on a clothing line.Nicole Ritchie tweeted this pic of her friend getting her hair dyed pink.

Michelle Trachtenberg also has designer aspirations, but hers are a bit more serious. She tweeted her congratulations to Rebecca Taylor, who recently opened a flagship store in NYC's Meatpacking District, adding, "So happy to be working on a collab with you!" Nicole Richie snapped this pic of her friend getting her hair dyed a bold pink. "I spy a little coconut," she tweeted, "& she is tickled pink! Any guesses on who it could be?" Her Twitter followers' guesses included stylist Simone Harouche, Avril Lavigne, and Richie herself (although it looks like that's her in the mirror taking the pic). Who do you think it is?

Lady Gaga & Alice Cooper.Mariah Carey tweeted a picture of her baby bump after an emergency visit to the hospital on her birthday.

Lady Gaga finally managed to find another celebrity with a similar freak-factor; she posed, covered in fake blood, with heavy metal rocker Alice Cooper, tweeting, "I just died and went to Hell." Last weekend, Mariah Carey went to the hospital for unexpected contractions – on her own birthday! To celebrate her birthday and the false alarm, she decorated her baby bump with a painted butterfly (half pink and half blue to represent the two sexes of her soon-to-be-born twins) and the phrase "dem babies." "My attempt @ festiveness on 327! For ATLITL thank u + I♥U! Comin soon#dembabies! LYMA+thanx 4 making me happy:)" the singer tweeted.