Dustin Diamond, best known for playing geeky sidekick Screech on "Saved by the Bell," is now behind bars in Wisconsin.
Diamond, 39, reported to the Ozaukee County Sheriff's Office Jail on Friday night to begin serving a four-month sentence related to a Christmas Day 2014 barroom stabbing.
The former TV star was also sentenced to 15 months of probation after being convicted in May on two misdemeanor counts of carrying a concealed weapon and disorderly conduct.
Police said Diamond used a switchblade knife to stab a man during a barroom brawl at the Grand Avenue Saloon in Port Washington, a suburb of Milwaukee.
Diamond said he pulled the knife to defend himself and his fiancée at the time, Amanda Schutz, who was found guilty of disorderly conduct.
Diamond and Schutz were also ordered to pay $1,500 in restitution to the stabbing victim, who suffered a non-life-threatening wound.