Was that their song? Justin Bieber sparks rumours of a rekindled romance with ex Selena Gomez as he serenades her with heartfelt rendition of My Girl

They've kept people guessing about the nature of their relationship for what seems like forever.

And Justin Bieber and ex-girlfriend Selena Gomez sparked fresh romance rumours as he was filmed serenading her in a luxury Los Angeles hotel bar on Friday evening, hours before he was pictured partying with newly-single Kylie Jenner.

The What Do You Mean? hit-maker burst into a heartfelt rendition of The Temptations' 1965 hit My Girl, which he directed at the Revival star, as they enjoyed a few friendly drinks together at the four-star Montage Beverly Hills hotel. 

Sparking fresh romance rumours: Justin Bieber was seen serenading his ex-girlfriend Selena Gomez in a Los Angeles hotel bar on Friday night, hours before he was pictured partying with newly-single Kylie Jenner

Sparking fresh romance rumours: Justin Bieber was seen serenading his ex-girlfriend Selena Gomez in a Los Angeles hotel bar on Friday night, hours before he was pictured partying with newly-single Kylie Jenner

A bystander captured the romantic moment and posted the footage on their Instagram account.

In the short clip, Justin, 21, is seen sitting down with a mic in his hand and a bashful-looking Selena, 23, perched next to him in the nearly-empty bar.

'Well, I guess you'd say. What can make me feel this way? My girl (my girl, my girl). Talkin' 'bout my girl (my girl),' he warbles to her.

See more of the latest news and updates on Justin Bieber and ex-girlfriend Selena Gomez 

Bursting into song: Justin, 21, took a pew next to Selena, 23, as he sang the lyrics to The Temptations' 1965 hit My Girl to her

Bursting into song: Justin, 21, took a pew next to Selena, 23, as he sang the lyrics to The Temptations' 1965 hit My Girl to her

Following the impromptu performance, the former couple - who split in 2014 - were pictured walking the streets of Beverly Hills.

In a frank interview with the Sunday Times in August, Selena admitted being in the public glare had affected her romance with Justin, which began when she was 19.

'I didn't think I was doing anything bad by falling in love,' explained the 23-year-old in the interview. 'There's such an emphasis on people being the perfect thing and then destroying them because it's good press.

'Also throw in the fact that you are a teenager - it makes it more difficult. The next relationship will be something dear to me. There is no way I will ever hide my life.'

On the lasting effect the relationship, which ended in 2014, has had on her life, Selena admitted: 'It's difficult for people to separate us. The internet wants to freeze this moment in time and constantly repeat it.' 

What Do You Mean? It's the first time the ex-couple have been pictured together in over a year

What Do You Mean? It's the first time the ex-couple have been pictured together in over a year

Just a few weeks later Justin hinted at his heartache over his on/off romance with Selena, during an interview with KIIS 1065's Kyle And Jackie O Show, confessing that he has been keeping himself to himself as his heartbreak has become too much for him to bear.

'I haven't been in a relationship for a while, I'm chilling and just hanging out. Just being by myself,' he told Kyle Sandilands and Jackie 'O' Henderson. 

'I am a relationship type of guy, I love to be in love and I love cuddling and I love all of that kind of stuff but I got my heart broken and so I'm just going to let that heal up. I had a few beers guys, maybe I'm talking too openly?' the 21-year-old added. 

It seems Justin and Selena's reunion on Friday was short-lived though as he was seen partying with newly-single Kylie Jenner, 18, who reportedly dumped her rapper beau Tyga, on his 26th birthday on Thursday, into the early hours. 

There is nothing to suggest Kylie and Justin's outing was of a romantic nature - rapper A$AP Rocky is also said to have been in the group - and it's common knowledge he's a close family friend, often attending their gatherings. 

On/off romance: Justin and Selena, pictured in 2011, split last year but have never fully cut ties with one another 

On/off romance: Justin and Selena, pictured in 2011, split last year but have never fully cut ties with one another 

The comments below have not been moderated.

The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline.

By posting your comment you agree to our house rules.

Who is this week's top commenter? Find out now