Selena Gomez knows social media. She has been such a saavy user of it that even being away for the last few months while dealing with the effects from Lupus, which caused her to cut her tour short, has not dulled her popularity. 

In fact Selena did something that no celebrity has accomplished before. Gomez reached 100 million followers on Instagram, the online mobile photo-sharing, video-sharing, and social networking service we all love so much. How did Selena reach this milestone? Here are five reasons that contributed mightily.

1. When Disney Girls Grow Up

The Disney entertainment machine has found a formula and has repeatedly been able to sell young women actresses as pleasing to young fans. But as they become of age, they find they have a male audience that follows their every professional step. Her bare body covered by silhouette as well as her first topless photo for V Magazine usually brings in the hits. "I love being happy with me," Selena posted on Instagram.

2. It Helps To Have A Relationship With Another Big Star

The whole "Jelena" drama, the are they, aren't they rumors, plus sneaky pictures that showed Selena and Justin Bieber  interacting in different settings, definitely had fans double checking her Instagram to see if she had posted anything new that could give them a hint of her personal life. But what might've brought her to ultimate Instagram super-stardom was when she made The Biebs quit the app once and for all after calling him out for not being cool with his fans when they all went against him for posting a photo with Sofia Richie, Lionel's daughter and an alleged girlfriend of the moment.

Justin-Bieber, Selena Gomez Oh memories! When Justin still had Instagram and Selena still liked him! Instagram/ Justin Bieber

3. Show The Sheikh Some Skin

Before the end of 2014, Gomez was in Abu Dhabi hanging out with Sheikh Zayed Grand Mosque. But in a photo in which she posed with the Skeikh covered almost completely in black, she caused a cultural controversy by baring her lower leg and ankle, both of which are not permitted.

Selena Gomez, Sheikh Zayed Grand Mosque Selena eventually took down this picture with Sheikh Zayed Grand Mosque from her Instagram, after causing controversy for showing her lower leg and ankle, both of which are not permitted in Abu Dhabi. Instagram/Selena Gomez

4. Being Friends With Jennifer Aniston

Being friends with a star that is universally loved like Jennifer Aniston always guarantees tons of hits from more than one fanbase. Call this "Guilt by Association." Here Gomez is hanging out with Aniston in 2015 as Jennifer was appearing in the film "Cake." Gomez was quoted on Instagram. "I have not only been following her career since I was eight and now get to watch her completely transform in her new movie."

5. Sultry Album Covers Sell 

"The Revival Tour" was launched by a photo that launched thousands and more hits. It is quite normal for artists to use album covers as a teaser for a project. Selena accomplished this by posing nude in a sitting position with one leg crossed and her long, dark hair strategically covering her breasts. Until her battle with Lupus forced her to slow down, this tour had the making of a personal best for the 24-year old.

So these mark the moments that made Selena Gomez the celebrity to watch. By being very fan-friendly, Selena has attracted a universe of popularity and made her Queen of Instagram.