Emma Stone and Andrew Garfield are reportedly on a break.
The couple - who have been dating for three years - are said to have temporarily called it quits on their relationship and it is thought the long distance between them is to blame.
The source said: "He's thrown himself in the project to the detriment of all else.
"But it's too early to say the relationship is over."
Andrew, 31, is currently on location in Taiwan, filming for the Martin Scorsese flick 'Silence' whilst Emma remains in the United States and despite the 'Birdman' star understanding her boyfriend's "work anxieties", they are both "slaves" to their careers.
The source added: "Emma understands his work anxieties - it's why she originally pulled out of 'Cabaret' last year and only did it this year - but they're taking a break from seeing each other.
"They're both a slave to their schedules. This time last year they were privately discussing marriage."
But there is hope for the pair as the insider revealed the notoriously private couple will be working on things between them without too much involvement from others.
The source told People magazine: "It's one of those situations where only Andrew and Emma quite know if they'll pick up where they left off or they've separated."