Carla Bruni has swapped the front row of the runway shows for the front row of political rallies, and Valerie Trierweiler has stopped writing about politics and started being written about.
The next first lady of France, an unofficial but much talked-about role, will be one of these two elegant companions, and both have had to adapt to a discreet but important role in their respective partners' campaigns.
At first, Bruni might appear better prepared for the campaign trail.
She was new to frontline politics when she married President Nicolas Sarkozy in early 2008 after a whirlwind romance but - as a former supermodel and girlfriend to several rock stars - she was used to celebrity life.
Trierweiler followed several election campaigns as a political journalist before and during her hitherto private partnership with Socialist challenger and campaign frontrunner Francois Hollande.
But she was so unused to the public eye that she expressed shock when she appeared on the front cover of her own glossy magazine, Paris Match.
In practice, both women have had to make serious adjustments to how they handle themselves in public, and both are seen as potential assets to the partners' campaigns, especially in touching a sceptical public.
"On the trail, I don't feel any aggression. People seem to like Nicolas. Anti-Sarkozyism is a phenomenon of the Parisian elite," said 44-year-old Carla, herself once the epitome of the Parisian art and fashion elite.
Where once she posed in an Elysee Palace stateroom in knee-high riding boots for the cover of Vanity Fair, now she plays the role of a simple stay-at-home mum, watching soap operas and caring for her infant daughter.
The Italian-born heiress has given a string of interviews about how she does not like to give interviews, complains of an alleged weight gain that is hard for the naked eye to discern and stresses the dedication of her spouse.
"He has an unimaginable sense of duty, Nicolas. He doesn't stop. He works all the time, he works 20-hour days. I'm afraid that he'll overdo it and kill himself," she told the weekly Nouvel Observateur.
While Bruni tries to stress the human side of her unpopular husband, her 47-year-old rival Trierweiler is supposed to add a little elegant glamour to a husband who may be too down to earth to seem truly presidential.
Bruni was the daughter of a wealthy industrialist, who grew up in luxury and travelled the world as a model and girlfriend to the rich and famous.
Trierweiler's father was disabled and her working-class mother did shifts at a provincial ice rink. She worked hard to make her way in journalism but until recently was always the political interviewer, not interviewee.
"What a shock to find oneself on the cover of one's own paper. Fury that they used the picture without my permission, and without warning me," she Tweeted, when her employer Paris Match moved her off the inside pages.
Her partner's campaign staff must have enjoyed the coverage more, however, as it was titled: "Francois Hollande's charming trump card".
Her private arrangements have also had complex political implications. Her predecessor in Hollande's affections was Segolene Royal, mother of his four children and his Socialist Party's defeated 2007 presidential candidate.
Trierweiler was already Hollande's partner during the 2007 race, but Royal and he kept their separation secret during the polling. Since then the former lovers have become rivals, standing against one another in the party primary.
Royal is still a figure in the party, and probably in any Hollande government, but it is now Trierweiler who works as the candidate's adviser -- with her own office at campaign headquarters.
Herself an elegant figure with flowing auburn hair, the mother-of-three is credited with helping Hollande shed 10kg and dropping his avuncular, jokey performances for a more presidential stance.
Bruni has no formal role in Sarkozy's campaign, unlike her own predecessor, Cecilia Ciganer-Albeniz, formerly Cecilia Sarkozy, who was a key adviser to her then husband in his victorious 2007 campaign.
That involvement ended in heartbreak both political and personal, however.
Sarkozy admits he made the great mistakes of his first weeks in office -- celebrating victory in a Champs-Elysees restaurant and a billionaire's yacht -- at a time when he was feeling the stress of his imminent break-up.
Bruni has no intention of repeating the mistakes that left her husband derided as the president of the rich and famous -- even if she did recently appear in a film directed by Woody Allen.
Her protestations of ordinariness are sometimes clumsy though. She triggered laughter when she said: "We are just modest French people."