Chris Brown and Drake are planning a ''surprise'' collaboration.
The pair - who have clashed on several occasions in the past - recently posted a picture of themselves hanging out in a recording studio together, and friends have now confirmed the artists have been working together on a track.
A friend of one of stars said: ''Make no mistake, that's going to happen. It will, but in time. Both of them like the element of surprise.''
Chris, 24, and Drake, 26, are also said to have been ''talking'' about getting others involved on their song, but it will depend on their fellow artists' availability.
The source added to HollywoodLife.com: ''Chris is trying to get 'X' out and Drake's enjoying the success of his new album sales.''
The pair have come to blows over mutual flame Rihanna several times in the past but they ended their feud by hugging at the iHeartRadio Festival in Las Vegas in September.
In June 2012, Brown and Drake had a bust up at a nightclub in New York, during which several people were injured after note passing about the 25-year-old beauty turned into a bottle-throwing brawl between the two love rivals and their respective entourages.