According to online records, Alexander's being held in a Tennessee jail. He was booked around 10:30 Wednesday morning ... and is currently being held on $50K bond. Unclear when he's due in court.

Of course, it's not the first time Jason -- who was married to Britney for just 55 hours in 2004 after a Vegas ceremony -- has been in trouble with the law.

TMZ broke the story, Jason busted into Britney Spears' home on her wedding day back in June 2022 repeatedly saying he needed to talk to Britney, despite the fact he wasn't even on her wedding guest list.

Alexander made it as far as Britney's bedroom door, cops say he was armed with a knife, but thankfully never came face-to-face with Britney. He was eventually pinned down outside the home by employees setting up for the wedding until cops arrived and took him into custody.

Britney got a 3-year restraining order against Jason for the incident, and he was hit with a slew of charges including felony stalking, vandalism, and trespassing battery.

He pleaded no contest to aggravated trespass and battery, both misdemeanors, and two charges were dismissed -- felony stalking and misdemeanor vandalism. Jason was sentenced to 128 days in jail for the wedding fiasco.