The Almost Famous star, who is the face of Ann Taylor's new advertising campaign, already has two children, both sons, but Hudson admits she keeps all her favourite gowns in the event she and fiance Matt Belamy add a little girl to their brood.
She tells the Associated Press, "I archive a lot of my pieces - from when Stella (McCartney) was at Chloe and Tom Ford at YSL and Gucci. My mum (actress Goldie Hawn) never kept her clothes. She was big into (Azzedine) Alaia clothes and she didn't keep them!
"She also had Ossie Clark dresses from the '70s, and I never got to wear them, so I decided when and if I have a little girl in my life, maybe she'll be into them and want to go into my closet someday."
The Pushing Daisies star recently decided to treat herself with a trip to a retro fashion fair in London, and spared no expense as she snapped up pricey new additions to her wardrobe.
A source tells Britain's Daily Express, "Vintage junkies love this fair because it has loads of samples by designers such as Alexander McQueen up for grabs and Anna was buying like there was no tomorrow.
"She bought dresses, twinsets and luggage and her bill came to £8,000. There was no stopping her."
But there was one item with a hefty price tag Friel couldn't seem to justify.
The insider adds, "She tried on a gorgeous Ossie Clark dress, which looked amazing but didn't quite fit. It was £800 (and) she put it back on the rail."