The California newspaper dedicated a large portion of its front page to Comey's prepared written testimony, released released earlier Wednesday, in which Comey confirmed President Donald Trump had asked him for "loyalty"and asked Comey to drop the FBI's investigation into his former national security adviser, Michael Flynn.
Trump also referred to the investigation of Russia's meddling in the 2016 US election as a "cloud" that is damaging his administration.
Comey will testify Thursday in his first public remarks since he was fired by Trump on May 9.
In preparation for Comey's testimony, Trump's team is said to be gearing up to undermine Comey's remarks.
The Washington Post reported Trump's top lawyers and advisers are reportedly encouraging the president to refrain from posting on social media during Comey's testimony on Thursday, out of concern for political and legal repercussions.
The advice echoes that of Trump's closest advisers who in recent weeks have sought to rein in Trump's social-media use, largely to no avail.