From The Insider:
Executive Producer CRAIG THOMAS says he is “thrilled” to have [Abby] back. “We’re all so thrilled to have [Abby] joining us once again. And just to head it off at the pass this time around: ‘Yes, Mom, [Abby's] very nice and no, I can’t get her autograph for you.’ “
And behind the jump, what the script says about Abby meeting the gang in 3.19.
Barney: Oh, wow, Ted, long time no see. I guess you’re wondering why I haven’t called in a while. See, I’m kind of done with the whole having a life and being awesome thing. Now I’m all about staying in, wearing loose-fitting clothing, and watching bad movies my girlfriend makes us watch.
Ted: That so?
Barney: I’m sorry, have you guys met my girlfriend, Abby? She’s my girlfriend, and I just love her love her love her. We’re in love, just like Tom and Katie. [Jumping up] I’m in love! And there’s nothing about it that makes everyone around me uncomfortable or annoyed!”