"The Marvelous Mrs. Maisel" star took to Instagram on Wednesday, June 05, to share an image of herself looking off into the distance during what appears to be a picnic.
"Missing Katy B today," Brosnahan wrote, adding two lime-green heart emojis.
Funnyman Spade also paid tribute to the fashion visionary, posting a photo of himself alongside Kate at an event in February, 2006 and adding a red heart emoji.
Spade, 55, committed suicide at her New York City apartment in June, 2018.
Meanwhile, representatives at her brand, Kate Spade New York, marked the sad anniversary with a touching dedication on social media.
"She was smart, chic, artful, witty, timeless, charming, trailblazing, gracious and so much more: kate spade inspired millions of women to stand out in a crowd," the post reads. "we honor the life of our visionary founder and all the joy and beauty she brought into this world. her vision inspires us every day".
Bosses at the company have donated $1 million (£790 million) to mental health organisations in Kate’s name to mark the anniversary.