The 24-year-old looked beautiful as she arrived at the BBC building on Thursday morning (27 June) wearing a floor-length black dress that flattered her baby bump, teamed with a patterned monochrome jacket.
She added a pop of colour with a vibrant blue bag.
Frankie was also looking rather bronzed from her recent sunshine holiday with footballer fiancé Wayne Bridge to the south of France.
They announced their engagement in April and followed up a few weeks later with the happy news that they're expecting their first child together.
In a picture uploaded to Twitter today by Una Healy, Frankie and her band mates were seen posing alongside Radio 2's Patrick Kielty. Una added the caption: "So happy all 5 of us together again!"
She was, of course, referring to Rochelle Humes' return to the band following her maternity leave. Rochelle welcomed daughter Alaia-Mai with JLS star husband Marvin in May.
Rochelle looked gorgeous in orange trousers and a black T-shirt, teamed with simple black heels and a light cardigan.
She officially returned to Saturdays duty last week, joining the girls at the launch of a brand new Marie Curie Hospice, which was also attended by Prince Charles.
Rochelle's last performance with The Saturdays was back in March at G-A-Y in London, and it seems she's finding it tough getting back into the spirit of rehearsals.
She tweeted yesterday: "Learning the Gentleman choreography for my performance come back lol. This Morning on Friday I'm scurred...@AaronRenfree going hard on me x."
We bet she pulls it off!