Gillian Sturgeon posted on Facebook at 5.35pm on Friday, before deleting the post following backlash.

Nicola Sturgeon’s sister has come under fire after posting about Princess Kate’s cancer diagnosis 25 minutes before the official announcement.

Gillian Sturgeon posted on Facebook at 5.35pm on Friday evening – 25 minutes before Kensington Palace shared the official video from the Princess of Wales.

After the post, Gillian was asked whether her older sister, the former First Minister of Scotland, had told her about the cancer diagnosis.

She denied the accusation, replying to the comment: “My sister and I haven’t spoken in three days. I read online. Stop using someone’s illness to try to troll. Sad person you are.”

Gillian Sturgeon deleted the post after getting backlash online (Image: Facebook)

Princess Kate shared her video message at 6pm on Friday (Image: BBC Studios)

Another social media user commented: “Some stooshie you’ve caused. Your poor sis getting it tight…. (sic)”

Gillian replied: “I’ve done nothing wrong. Neither has she. I read something online but Ofcourse people want to believe the other.”

Though Nicola Sturgeon is no longer the First Minister of Scotland, she is still on the Privy Council which serves as an important link of communication between the minister and the constitutional authority of the sovereign.

After deleting the post, Gillian made another post, explaining that her original post had been deleted.

She wrote: “Goodnight trolls. Goodbye [waving hand emoji] also. Lots blocked. Post down – and no more explanations given. What I read online I have no control over.”

Princess Kate announced her cancer diagnosis in a personal two-minute video message shared at 6pm on Friday.

Since the announcement, fans have rallied around the Princess, sending their well wishes and offering support.

Kensington Palace has not disclosed what stage the cancer is at, but remains “wholly positive” Kate will make a full recovery.