TMZ later reported Spears' ex-husband successfully made it into the singer's property, where he continued to live stream before being restrained by security once more.
Ventura County Sheriff's Department was called and quickly responded to the incident before charging Alexander with trespassing, vandalism and battery charges.
He is currently being held on US$2500 (NZ$3927) bail. The NY Times has reported Alexander was also wanted for grand theft embezzlement and possession of stolen property, and bail was set at $20,000 ($31,420).
A new report from Page Six has further revealed Alexander was "armed with a knife" when he trespassed on Spears' property and that was warned ahead of the wedding that he was "not welcome".
Spears' lawyer, Mathew Rosengart, told Page Six: "Jason Alexander has been handcuffed, taken into custody and arrested. I express my thanks to the Ventura County Sheriff's Department for their prompt response and good work."
He added: "I'm working closely with law enforcement to ensure Mr Alexander is aggressively prosecuted to the fullest extent of the law".
It is not known if Spears and Asghari's ceremony had already begun when her ex-husband crashed the event.
Spears was romantically linked to Asghari in 2016 after meeting on the set of the singer's Slumber Party music video. However, it wasn't until five months later that the pair got in touch again.
Asghari revealed to GQ in June: "It was the humbleness that attracted me," adding, "She was very humble and she had a beautiful soul."
The pair got engaged in September after dating for five years.
