Charlie Sheen may be back to his bad behavior already.
According to a TMZ report, the Two and a Half Men star, 45, was seen taking shots of Grey Goose vodka alongside a female companion during an outing at The Palms hotel in Las Vegas Monday.
What's more, according to a witness, the actor -- who was staying in the $40,000-a-night Hugh Hefner Sky Villa inside the hotel's fantasy tower -- was complaining to fellow bar patrons that CBS execs have been urging him to go to rehab.
This latest bar visit comes as no surprise to one insider, who tells UsMagazine.com Sheen recently ditched his sober coach -- an aide who was hired after the father of five trashed an NYC hotel room during his infamous October 25 bender.
"The sober coach never went back to work for Charlie," says the source. "He has not heard from Charlie since he told him not to start New Year's day!"