Tom Cruise Intruder -- Swears It Was an Honest, Drunken Mistake

Jason Sullivan is telling friends ... he blames his arrest on the ah-ah-ah-ah-ah-alcohol ... 'cause he was so drunk when he returned to Bev Hills last night, he mistook Tom Cruise's home for the Bev Hills pad where he lives.

Sources connected to Sullivan tell TMZ ... Jason was out partying late with friends Sunday night ... and knew he was too drunk to drive home, so he responsibly got a ride from a sober friend.

We're told the friend dropped Jason off near the Bev Hills home where Sullivan has been living ... but in the moments after he exited the car, the drunk Australian interior decorator became confused ... and tried to enter an adjacent home ... which happens to belong to Tom Cruise.

As we previously reported, cops were called by someone reporting an intruder at Tom's home ... and when they arrived to the scene, security guards had already tased Sullivan and then he was arrested for trespassing.

Sources say ... Jason sustained some pretty gnarly injuries from the taser on his back -- and is sporting some nasty bruises.