The Full Hollywood Reporter reports that actress January Jones, star of the popular HBO series “Mad Men”, described how her character Betty Draper Frances evolved into “Fat Betty” in season five.

At the time, she was in the third trimester of her pregnancy and rather than try and hide her weight gain, series creator Matt Weiner, had her character putting on the weight. The new “Fat Betty” character became an internet sensation.

Jones herself was very pleased at how her pregnancy weight was accommodated into the show but it wasn’t all love. Jones said “”I was in seven hours of prosthetics every morning, trying to rip off a fake chest piece so I could breastfeed… 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.”

January Jones Love-Hate Relationship With Character's Fat Betty