Britney Spears Wedding Crasher Jason Alexander Allegedly Tried Entering Bedroom - TMZ

One of Britney's security guards -- who's since been fired over the incident -- told the judge Alexander beelined it straight for Britney's bedroom after sneaking onto the property and getting inside the main house.

The guard testified, Alexander tried opening Britney's bedroom door while she was inside, but it was locked.

Alexander, who cops say was armed with a knife, live streamed himself getting onto Britney's property and up to the second level of her home, demanding to see her on her wedding day.

The security guard, who got fired by Britney shortly after the incident, also testified Alexander had been spotted on the outskirts of the property multiple times leading up to the wedding ...