Luke Hemmings, arguably the leading man of the popular 5 Seconds of Summer, seems to have a case of a sad girlfriend on him. The girlfriend (now ex) Aleisha McDonald is also a singer. They even have a video of them singing a cover of 'She Will be Loved' by Maroon 5 floating around on Youtube. But something went awry and Luke Hemmings and girlfriend Aleisha McDonald ended their relationship as Luke Hemmings' band, 5 Seconds of Summer, took off. What could have possibly caused the break up of these two song birds? Are crazy 5 Seconds of Summer groupies to blame?

Aleisha McDonald, according to her Twitter and Instagram, attends the same school, is a Christian and says that music is her life. She currently has a band consisting of two other people, one drummer and one violinist, doing great covers of famous songs.

She also writes original songs! She wrote on her Twitter, "I've been writing songs non stop for so long now :) I hope I can show them to you some time soon."

Aleisha McDonald has also been on The Voice and constantly churns out new videos with her rendition of popular songs.

But it looks like music can't get the ex-girlfriend of Luke Hemmings to stop thinking about her musician boyfriend. Aleisha McDonald posted on her Twitter recently that she thinks about him a lot:

woah, I think about you a lot

— Aleisha McDonald (@aleisharuthless) May 15, 2014

Many 5 Seconds of Summer fans speculate that the band's meteoric rise to fame affected the couple's relationship. Since Luke Hemmings started to travel a lot, and enjoy the fame and attention from other female fans, he may have become disinterested in his girl back home in Sydney. Others speculate that the 5 Seconds of Summer groupies played a hand on the disintegration of their relationship.

Aleisha McDonald wrote on Pintrest less than a year ago, "Why did we break up :(". To that, Luke Hemmings curtly wrote back ":\".

Meanwhile Luke Hemmings has been having a wild time on the tour with One Direction. At one concert, he said "Alright, this is a new song, it's called 'All I Need'. Yes, this song is about boobs." Definitely something a guy without a girlfriend would say.

He also said that he would date a fan and somebody about 2 years younger than he is.

Looks like Luke Hemmings has forgotten about Aleisha McDonald. But he should stay away from dating young 5SOS groupies. Things can get ugly really quickly.