On the sixth season premiere, Charlie encounters an ex-girlfriend whose son looks an awful lot like him.

Alan lends Charlie money and crosses a line in his attempts to get it back.

Charlie tries cooking, Alan tries dating two women at the same time and Jake (series star ANGUS T. JONES) tries beer.

Charlie romances Alan's sweet receptionist as Alan anxiously awaits disaster.

The guys bump into Jake's former teacher, Miss Pasternak. Charlie tries to help her out by giving her a room and a job, but things spiral out of control.

When Judith kicks Herb to the curb, Alan comes knocking.

Alan tries to escape Judiths grasp as Charlie and Herb go on the prowl.

Charlie's new girlfriend, Chelsea asks him to spend the night at her place, while Alan tries to enforce a punishment on Jake.

Jake disappears with the daughter of Charlie's neighbour, a former NFL player (guest star MICHAEL CLARKE DUNCAN), and Charlie is left to cover his back.

Evelyn offers to pay for Jake's college education, leaving Alan to wonder if he ever needs to work again.

One of Charlie's old partners in crime dies, leaving Charlie to reevaluate his own reckless lifestyle.

Charlie and Jake fight for the affections of a waitress, while Alan fights sexual tension with his receptionist. Multiple Emmy® Award winner CAROL KANE guest stars as Melissas mother.

Judith is pregnant with a baby girl and Alan is convinced that he is the father.

Convinced that Alan's family doesn't fully appreciate him, Melissa invites Alan to live with her and her mom.

Charlie finds himself in couples counseling.

Charlie has to remove a half-naked woman from his bedroom before Chelsea arrives.

Charlie tells Chelsea (guest star JENNIFER TAYLOR) that he loves her, but doesn't get the response he expects.

Chelsea gets sick - and Charlie wants nothing to do with her.

Charlie joins Alan, Herb and his next-door neighbor in a night of alcohol-fueled sexual reminiscences after Chelsea finds nude pictures of another woman on his phone.

Evelyn finally meets Chelsea and Charlie - then tries to prevent them from becoming friends.

Chelsea sets Alan up on a blind date with her new friend Rose.

After Charlie reluctantly agrees to let Chelsea move in and he mourns the loss of his bachelor pad, Alan finds that there's not much space left for him in the house.

Alan and Chelsea become best friends; and Charlie likes it.

Charlie questions his relationship with Chelsea when he hears that Mia is back in town. Meanwhile, Judith goes into labor and Charlie, Alan and Herb rush her to the hospital.