AnnaLynne's Birthday Bash -- Pool Party Pics!

AnnaLynne McCord celebrated her 23rd birthday this weekend in Las Vegas -- where her spirits (and hot bod) were lifted by boyfriend Kellan Lutz.

The "90210" star partied poolside at the MGM's Wet Republic on Saturday with the "Twilight" star and her sis Angel.

Earlier last week, McCord was back on set filming for the new season of "90210," which starts September 13.