Biden makes surprise visit to Beau's widow and Hunter's ex Hallie just a week before she is set to testify in the president's son's federal gun trial

President Joe Biden stopped to see Hallie Biden, the widow of the late Beau Biden and son Hunter's ex, on his way back to Washington D.C. on Sunday night, just a week before she is scheduled to testify in his son's trial.

Biden spent about 15 minutes at her home in Wilmington, Delaware. His motorcade stopped there in route to the Delaware National Guard Station, where Biden would lift off on Marine One to return to the White House. 

White House spokesman Andrew Bates said the president didn't discuss the trial with Hallie Biden during the visit.

'No,' he replied. 'He visited her because of the approaching 9th anniversary of Beau's passing.'

May 30th marks the anniversary of Beau Biden's death from cancer.

In addition to Hallie Biden, Hunter's ex-wife Kathleen Buhle and his ex-girlfriend Zoe Kestan will also testify in the trial, where Hunter faces three charges related to illegal possession of a gun. If convicted, he faces up to 25 years in prison. He has pleaded not guilty. 

The trial is scheduled to begin in Wilmington, Delaware, on June 3rd. 

Special counsel David Weiss alleges that Hunter Biden unlawfully purchased and kept a Colt Cobra 388PL revolver in October 2018 and made false statements on a form used for gun purchases, claiming he was not an unlawful drug user. 

Then Vice President Joe Biden, Jill Biden, Beau and Hallie Biden in February 2012

None of the women were named in the court papers but they do state that 'Witness 1 was previously married to the defendant' and that 'she would check his vehicle from time to time because she did not want their children in a vehicle with drugs.'

Hunter and Kathleen separated in October 2015, five months after Beau Biden's death.

Witness 3, according to the filings 'was in a romantic relationship with the defendant in October 2018, and before and after.' 

And it also references Witness 2, a woman who 'was previously in a romantic relationship' with Hunter and 'observed the defendant using crack cocaine frequently—every 20 minutes except when he slept.'

Hallie and Hunter dated in 2017, two years after Beau Biden died of brain cancer. Hunter has said the relationship developed out of their shared grief over Beau. 

In May 2019, Hunter wed South African filmmaker Melissa Cohen. Their son Beau was born in March 2020. 

Witness 1 is alleged to be Buhle, 2 to be Hallie Biden and 3 to be Kestan. 

It's unclear if Hunter will take the stand in his own defense.  

It's expected the trial will last up to nine days.

Hunter Biden has acknowledged an addiction to crack cocaine during the period in which he purchased the gun but his lawyers have said he didn't break the law and the case is politically motivated. 

But prosecutors won a victory on a key point as U.S. District Judge Maryellen Noreika found that they wouldn't have to prove that he specifically used drugs on the day of the purchase. 

Judge Noreika, however, agreed to a defense push to keep out other details about his past, including a child-support case in Arkansas and his dismissal from the Navy after a positive drug test. 

Hunter Biden and Hallie Biden started dating two years after Beau Biden died

Hunter has said the relationship developed out of their shared grief over Beau

President Joe Biden visited Hallie Biden's house in Wilmington, Delaware

Hunter Biden's trial begins June 3. He is seen outside court last week for a pre-trial appearance

Also next month, Hunter Biden could go to trial on the opposite coast for the case involving tax evasion. That trial is scheduled to start June 20. 

He's accused of failing to pay at least $1.4 million in taxes over four years while living an 'extravagant lifestyle' during a period in which he has acknowledged struggling with addiction. The back taxes have since been paid.  

If convicted in the case, Biden faces a maximum of 17 years in prison.