Those 'bitches' Shang Tianyi referred to were Mu Xiaoya, and Su Han, the second supporting actress in the show.
Su Han had been in the entertainment world for many years, and her acting skills had been recognized, but she hadn't been very popular. She had met Ye Shengge in the script reading before but she didn't show any respect to Ye Shengge who was a newcomer in the lead actress role.
Su Han was putting on makeup when Ye Shengge walked in. She saw Ye Shengge in the mirror and rolled her eyes. Meanwhile Mu Xiaoya was going through gowns in front of the rack. She appeared fussy as if she wasn't satisfied with any of them.
"They're all second and third-tier brands." Mu Xiaoya yelled at her agent, Song Yihai. "I only wore D.C. and a Little Frangant House when I attended the previous event."