NEW YORK (TheStreet) -- As the market for tech start-ups continues to heat up, celebrities are starting to get into the game.

While some like Two and a Half Men star Ashton Kutcher are well-known for investments in high-profile companies like Foursquare, Airbnb and Chegg, other tech-savvy celebs are more surprising.

Here are six stars looking to dip their toes into Silicon Valley.

Selena Gomez

Disney

star Selena Gomez recently participated in a $750,000 funding round for a new app called

Postcard on the Run

. The service lets users print out and send photos to friends and family using their iOS or Android phone.

Postcard on the Run, which competes with apps like

Postagram

and

Apple's

(AAPL) - Get Report

Cards, recently added a new feature that lets users add scratch n' sniff scents like fresh flowers, bubble gum and popcorn to their postcards for an additional 50 cents.

While new to tech investing, Gomez is powerful within the social media sphere. She boasts more than 8.5 million

Twitter

followers and nearly 25 million

Facebook

fans. She will also serve as a creative adviser to Postcard on the Run.

Gomez may have also inspired boyfriend Justin Bieber to consider tech investing -- the pop sensation is reportedly looking to become an angel investor in early start-ups.

Lady Gaga

Pop superstar Lady Gaga clearly has good taste when it comes to start-up investing. In June, the

Born This Way

singer was part of a team including

Google

(GOOG) - Get Report

Executive Chairman Eric Schmidt to raise $1 million for social network

Backplane

.

Started by Lady Gaga's manager Troy Carter, Backplane is still in stealth mode but hopes to create an interactive platform for brands centered around specific interests, like sports and entertainment.

Gaga holds a 20% stake in the company.

While BackPlane is Gaga's first start-up investment, it's not her only foray into the tech space. Last year, she worked with social games company

Zynga

to create GagaVille, an offshoot of its FarmVille game, in which users try to win virtual items like unicorns and crystals.

She's also collaborated with flash sales site

Gilt Groupe

for a charity auction and has worked with Google and

Polaroid

.

Kim Kardashian

America's favorite reality star, Kim Kardashian, is also a savvy tech investor.

Kardashian is one of the partners in

ShoeDazzle

, an e-commerce site that asks users to take a personality quiz, and every month selects five pairs of shoes, handbags and jewelry for a customer based on her survey results.

Subscribers pay $39.95 per month for the service.

In May, the company raised $40 million from venture firm Andreessen Horowitz, which has also invested in top tier start-ups like Facebook, Foursquare and Twitter.

Kanye West

Rapper Kanye West is a rumored investor in music start-up

Turntable.fm

, which raised $7 million this summer.

The company lets users discover music by placing them in a virtual DJ room in which they can rate songs up or down. Popular rooms include: "Indie While You Work," "I Love the 80s," and "DJ Wooooo's House/Dance/Electro."

As of September, the site had more than 600,000 users and streamed 1 million songs a day.

One of the most buzzed about start-ups of the year, Turntable also gave a board seat to high-profile venture capitalist Fred Wilson of Union Square Ventures as part of the investment.

Leonardo DiCaprio

In October, DiCaprio became the latest investor -- and adviser -- to Israeli photo sharing app

Mobli

.

DiCaprio participated in the company's $4 million Series A round in his first tech investment.

The app lets users share videos and photos through subject-based channels in real-time. For example, if you were at a concert but had bad seats, you could use the app to get a different angle of the stage based on other users' uploads of the venue.

The app attracts more than 10,000 users a day, and is available on iOS, Android and BlackBerry. Besides DiCaprio, other celebrity users include Paris Hilton and David Arquette.

MC Hammer

Rapper MC Hammer is an angel investor, social media guru and early adopter of now ubiquitous tech start-ups.

One of the first users of both Twitter and

YouTube

, Hammer has been called "a tech visionary" by close friend and legendary angel investor Ron Conway.

He's an investor in buzzy mobile payments company

Square

, dance-oriented social network

DanceJam

as well as

Bump Technologies

, which lets users share contact information by bumping their smartphones together.

Last month, Hammer also announced

WireDoo

,

a so-called relational search engine that he's involved with

.

--Written by Olivia Oran in New York.

>To follow the writer on Twitter, go to

http://twitter.com/Ozoran

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