A stunning social media star has shocked her online fans after she showed them a black eye she got after she ended up in between a couple arguing.

Lena Mantler, 21, made headlines when she and her twin sister Lisa, held the number one most-followed account with over 30 million devoted fans on the platform ‘Musical.ly’, now known as TikTok.

Now Mantler, from the city of Stuttgart, Germany, shocked her 21 million Instagram followers when she posted a few snaps showing her with a black eye and a bruised cheekbone.

It reportedly happened after she was hit when she got in the middle of a heated argument between a couple earlier this week.

Lena said: “I was on the way home and saw a man and a woman arguing, especially in situations like this, a lot of people look away, I think because we’re all afraid that we’ll get into trouble.

“That’s exactly what happened to me, but I’m still glad that I tried to help, even though I now have a nice smokey eye.”

She continued: “I already told you that this is the second time that something like this has happened to me.

“The first time was a year ago, but the difference is that back then I was the victim and I wished that someone would have said something and helped me out of the situation.

“That is why I tried to help. Some people texted me similar stories and it’s heartbreaking to know that it happens more than we think.”

She however reassured her fans that she is doing fine, by adding: “I’m feeling good though!”

Lena said: “But whenever you are in a situation like this or walk by, don’t just look away. Maybe call the police first, I will definitely remember that.”

The gorgeous blonde did not reveal whether she filed a complaint against the person who hit her.