Prosecutors are expected to conclude their case next week, paving the way for the defence to begin calling witnesses – a point at which Kanye may make an appearance.
Combs has pleaded not guilty to all charges and has denied all allegations of misconduct.
More than 60 civil suits have also been filed against Combs alleging sexual assault or other abuses on top of his criminal trial.
The source also confirmed to CNN that Christian and Kanye are currently collaborating on new music.
They previously worked together on a track released in March, which included audio of a jailhouse phone call between West and Combs.
The track also featured vocals from Kanye’s daughter with Kim Kardashian.
Scandal-plagued Kanye, who has been widely criticised in recent years for repeated anti-semitic remarks and inflammatory behaviour, is one of the few public figures to voice support for Combs.
Before his fellow rapper’s trial, he posted messages on social media advocating for Combs’ release.
In February, West sparked further backlash after he promoted and sold T-shirts emblazoned with swastikas – an incident he publicised in a Super Bowl advertisement.
Neither Combs nor Christian responded to CNN’s request for comment.
