Justin Bieber and Selena Gomez kiss in Norway

Justin Bieber and Selena Gomez shared a passionate kiss in Norway.

The pop stars were spotted secretly smooching backstage during Justin's April 18 concert in Oslo, Norway, confirming rumours they had rekindled their romance after originally splitting just before New Year's Eve (31.12.12).

A source told UsMagazine.com: 'Justin pursued Selena and she gave in. They have a crazy connection.'

However, the 'Baby' hitmaker and the Disney starlet are taking things slow and have no plans to make things official yet.

The insider added: 'They aren't back together.'

The couple fell out after an explosive row on holiday in Puerto Vallarta and have had little contact since. Selena shocked fans by flying out to Oslo last week, but has apparently been secretly missing Justin since her promotional whirlwind for her new movie 'Spring Breakers' came to an end.

Another source joked: 'Who knows with them? They're always back and forth!'

Speculation the pair had got back together was fuelled when Justin accidentally posted a photo of the his Instagram account over the weekend, before quickly removing it.

Selena's pals are said to be furious she is thinking of reconciling with Justin, who they believe is a bad influence on her.

An insider recently said: 'They've been spending a lot of time together, secretly, over the last couple weeks. But nothing is official between them.

'Being with Selena is good for him, but her friends are adamant that he's bad for her.'