Laureen Harper is jumping on the "Fifty Shades of Grey" bandwagon to promote a feline cause close to her heart.

In a message on her Twitter feed, the prime minister's wife is encouraging people to adopt one of the grey cats up for adoption at the Windsor Essex County Humane Society in southwestern Ontario.

The promotion was launched as "Fifty Shades of Grey" opened in movie theatres in time for Valentine's Day.

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The R-rated movie, an adaptation of E.L. James's bestselling trilogy, has been panned by some critics for glamorizing sexual violence against women.

To encourage cat adoptions, the Windsor Essex animal shelter is reducing its adoption fees Saturday for all grey cats to $50 in a promotion dubbed "Fifty Shades of Grey" — Cats.

Laureen Harper is well known for her love of cats. She and her kids have fostered a number of them in the prime minister's official residence at 24 Sussex Drive.

"This Valentines, head to windsorhumane — they're adopting all shades of grey cats for only $50," Harper tweeted Friday.

The message included a poster picture of a grey cat, with a caption below it that read: "Due to the nature of this program, adult cats only."

The Windsor shelter has roughly 15 grey cats up for adoption.

It normally charges a $125 adoption fee for felines five months or older.