Who? Rochelle Humes and Frankie Sandford of The Saturdays.
What? Adding some Spice to their lives! Both girls attended a 90s fancy dress party for Aaron Renfree (former member of S Club 8 along with Frankie), and both girls decided to go as a Spice Girl. Rochelle chose Mel B, and showed off her tiny baby bump in a tiger-print catsuit. Frankie opted for Posh, and chose a sleek LBD with a shiny bob hairdo.
Rochelle's husband, JLS' Marvin, also got in on the act and turned up dressed as MC Hammer.
Where? London, 18 December.
Verdict? Best-dressed has to go to Rochelle, for making the effort with a baby on board. Look back at The Saturdays' style evolution below...