"Thank you to all the supporters of The Tig!" she wrote. "From followers to contributors, you have become friends It is YOU who have made this Tig community so special.
"And even though I haven't met most of you, for three years I've seen your faces and read your comments and hugged you from afar. (Domi, Em, Hannah, Sol, Iris, Doris, Jessy, Simone, Cassy....and so many more! I will always be grateful for your support).
"Go to @thetigofficial or thetig.com to see our official send-off. Sending all the love xx MM #TigFarewell"
She didn't explain exactly why she was shutting the website down, but we can probably guess it's because she's busy with her role in Suits, her philanthropic work for the UN, and other projects.
The star is also dating Prince Harry, with Kensington Palace making an official announcement last November.
This article previously appeared on marie claire.