January Jones became Fat Betty for a reason. When the actress started Season 5 of "Mad Men," she was eight months pregnant. By the time filming the season had wrapped, she had a five month old. In an effort to conceal her pregnancy, her character Betty put on the pounds.

"I was in seven hours of prosthetics every morning, trying to rip off a fake chest piece so I could breastfeed," Jones said in a new roundtable interview with The Hollywood Reporter. Jones, Julianna Margulies of "The Good Wife," Claire Danes of "Homeland," Kyra Sedgwick of "The Closer," Emmy Rossum of "Shameless" and Mireille Enos of "The Killing" all sat down for an interview with THR to discuss being leading dramatic actresses on TV.

When asked about the Fat Betty direction, Jones said she "loved it." "I didn't want to try to hide it. I thought it would become comical and weird," Jones said. "I also didn't want to have the character become pregnant because it just wouldn't make sense -- she had just had one. And I thought it would be something fun, not realizing it was going to be a pain ... It was definitely difficult, but I love what [Matt Weiner] did with the character's story. Everyone likes a challenge."

Fat Betty became an internet sensation and Jones has heard about the @FatBettyFrancis Twitter account. "That's crazy," she said.

Margulies said she thought the Fat Betty twist was "awesome." "I thought it was so brave," she said. "And great."

Jones went on to say her grandfather said she looked "a bit fuller, but still beautiful," thinking it was all pregnancy weight. "I thought I was watching Eddie Murphy in 'The Klumps' ... I was like, 'My career is over,'" she said with a laugh. Jones didn't watch the episode ahead of air and admitted it took her a while to get through it.

As for her challenges on "The Good Wife," Margulies said, "As much as I'd like to pretend it's an ensemble, it's not.

"It's 'The Good Wife,' and if the good wife goes down, there's no show," she said with a laugh. "My problem is, I'm not a squeaky wheel ... I'm a worker; I can wait tables. So I have this idea that I'm one of the crew, but the problem is I have to perform and have to be there two hours before the crew gets there and then work two hours when everyone goes home ... So my biggest challenge has been to say, 'Guys, guess what? I can't be in the background of so-and-so's scene,' because that would give me two hours with my kid. Or, how about an hour to sleep, go to the gym. Or learn a line or two. Don't just use me because I'm here all the time. I have to prepare and have a life. So that's been my hardest challenge, hopefully in Season 4 -- I'll be in a court scene for 14 hours without a line and that's craziness to me ... So they're going to work on that."

Watch the full, uncensored THR interview below and click over to THR for more from January Jones, Julianna Margulies, Claire Danes, Kyra Sedgwick, Emmy Rossum and Mireille Enos.

For more photos from "Mad Men" Season 5, click through the slideshow below:

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  • Season 5, Episode 1: "A Little Kiss"

    Meredith (Stephanie Drake) and Joan Harris (Christina Hendricks)

  • Season 5, Episode 1: "A Little Kiss"

    Joan Harris (Christina Hendricks) and Roger Sterling (Jon Slattery)

  • Season 5, Episode 1: "A Little Kiss"

    Peggy Olson (Elisabeth Moss)

  • Season 5, Episode 1: "A Little Kiss"

    Megan Draper (Jessica Pare)

  • Season 5, Episode 1: "A Little Kiss"

    Megan Draper (Jessica Pare)

  • Season 5, Episode 1: "A Little Kiss"

    Don Draper (Jon Hamm), Roger Sterling (John Slattery) and Lane Pryce (Jared Harris)

  • Season 5, Episode 1: "A Little Kiss"

    Don Draper (Jon Hamm), Roger Sterling (John Slattery), Lane Pryce (Jared Harris) and Betram Cooper (Robert Morse)

  • Season 5, Episode 1: "A Little Kiss"

    Don Draper (Jon Hamm)

  • Season 5, Episode 2: Tea Leaves

    Henry Francis (Christopher Stanley)

  • Season 5, Episode 2: "Tea Leaves"

    Henry Francis (Christopher Stanley) and Betty Francis (January Jones)

  • Season 5, Episode 2: "Tea Leaves"

    Betty Francis (January Jones)

  • Season 5, Episode 2: "Tea Leaves"

    Cecilia (Mari Weiss)

  • Season 5, Episode 2: "Tea Leaves"

    Michael Ginsberg (Ben Feldman)

  • Season 5, Episode 2: "Tea Leaves"

    Peggy Olson (Elisabeth Moss) and Michael Ginsberg (Ben Feldman)

  • Season 5, Episode 2: "Tea Leaves"

    Raymond Geiger (John Sloman) and Alice Geiger (Robin Pearson Rose)

  • Season 5, Episode 2: "Tea Leaves"

    Betty Francis (January Jones), Joyce Darling (Adria Tennor), and Cecilia (Mari Weiss)

  • Season 5, Episode 2: "Tea Leaves"

    Betty Francis (January Jones), and Joyce Darling (Adria Tennor)

  • Season 5, Episode 2: "Tea Leaves"

    Peggy Olson (Elisabeth Moss)

  • Season 5, Episode 2: "Tea Leaves"

    Megan Draper (Jessica Pare) and Don Draper (Jon Hamm)

  • Season 5, Episode 3: "Mystery Date"

    Dawn Chambers (Teyonah Parris)

  • Season 5, Episode 3: "Mystery Date"

    Dawn Chambers (Teyonah Parris)

  • Season 5, Episode 3: "Mystery Date"

    Dawn Chambers (Teyonah Parris) and Peggy Olson (Elisabeth Moss)

  • Season 5, Episode 3: "Mystery Date"

    Greg Harris (Samuel Page), Joan Harris (Christina Hendricks) and Gail Holloway (Christine Estabrook)

  • Season 5, Episode 3: "Mystery Date"

    Greg Harris (Samuel Page), Joan Harris (Christina Hendricks) and Gail Holloway (Christine Estabrook)

  • Season 5, Episode 3: "Mystery Date"

    Gail Holloway (Christine Estabrook)

  • Season 5, Episode 3: "Mystery Date"

    Joan Harris (Christina Hendricks) and Gail Holloway (Christine Estabrook)

  • Season 5, Episode 3: "Mystery Date"

    Michael Ginsberg (Ben Feldman)

  • Season 5, Episode 3: "Mystery Date"

    Ken Cosgrove (Aaron Staton)

  • Season 5, Episode 3: "Mystery Date"

    Jon Hamm (Don Draper) and Michael Ginsberg (Ben Feldman)

  • Season 5, Episode 3: "Mystery Date"

    Don Draper (Jon Hamm) and Michael Ginsberg (Ben Feldman)

  • Season 5, Episode 3: "Mystery Date"

    Michael Ginsberg (Ben Feldman)

  • Season 5, Episode 3: "Mystery Date"

    Greg Harris (Samuel Page)

  • Season 5, Episode 4: "Signal 30"

    Pete Campbell (Vincent Kartheiser), Jenny Gunther (Amanda Bauer)

  • Season 5, Episode 4: "Signal 30"

    Peggy Olson (Elisabeth Moss) and Joan Harris (Christina Hendricks)

  • Season 5, Episode 4: "Signal 30"

    Lane Pryce (Jared Harris)

  • Season 5, Episode 4: "Signal 30"

    Joan Harris (Christina Hendricks) and Peggy Olson (Elisabeth Moss)

  • Season 5, Episode 4: "Signal 30"

    Roger Sterling (John Slattery), Don Draper (Jon Hamm), Lane Pryce (Jared Harris) and Pete Campbell (Vincent Kartheiser)

  • Season 5, Episode 4: "Signal 30"

    Pete Campbell (Vincent Kartheiser)

  • Season 5, Episode 4: "Signal 30"

    Trudy Campbell (Alison Brie)

  • Season 5, Episode 4: "Signal 30"

    Trudy Campbell (Alison Brie)

  • Season 5, Episode 4: "Signal 30"

    Pete Campbell (Vincent Kartheiser)

  • Season 5, Episode 4: "Signal 30"

    Megan Draper (Jessica Pare) and Don Draper (Jon Hamm)

  • Season 5, Episode 4: "Signal 30"

    Trudy Campbell (Alison Brie)

  • Season 5, Episode 4: "Signal 30"

    Cynthia Cosgrove (Laria Oleynik), Trudy Campbell (Alison Brie), Megan Draper (Jessica Pare), Don Draper (Jon Hamm), Pete Campbell (Vincent Kartheiser), and Ken Cosgrove (Aaron Staton)

  • Season 5, Episode 4: "Signal 30"

    Don Draper (Jon Hamm), Pete Campbell (Vincent Kartheiser) and Ken Cosgrove (Aaron Staton)

  • Season 5, Episode 4: "Signal 30"

    Cynthia Cosgrove (Laria Oleynik), Megan Draper (Jessica Pare) and Trudy Campbell (Alison Brie).

  • Season 5, Episode 4: "Signal 30"

    Pete Campbell (Vincent Kartheiser), Ken Cosgrove (Aaron Staton), Don Draper (Jon Hamm) Cynthia Campbell (Larisa Oleynik), Megan Draper (Jessica Pare) and Trudy Campbell (Alison Brie)

  • Season 5, Episode 5: "Far Away Places"

    Megan Draper (Jessica Pare) and Don Draper (Jon Hamm)

  • Season 5, Episode 5: "Far Away Places"

    Megan Draper (Jessica Pare) and Don Draper (Jon Hamm)

  • Season 5, Episode 5: "Far Away Places"

    Megan Draper (Jessica Pare)

  • Season 5, Episode 5: "Far Away Places"

    Don Draper (Jon Hamm)

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