Olga Roh, 43, who owns the Rohmir fashion label, is now the Baroness of Inchdrewer, after buying Inchdrewer Castle near Banff, Aberdeenshire, for £400,000.
Her husband, Dr Stephan Roh, becomes the Baron of Inchdrewer.
The mother-of-three, who appeared on reality TV series Meet the Russians last year, bought the castle following the death of its previous owner, Count Robin de la Lanne-Mirrlees - who lived at Great Bernera in the Outer Hebrides.
Count Robin's lawyers, Ken MacDonald and Co, based in Stornoway on the Isle of Lewis, said the title was being transferred to the couple. An application for assignation had been made to the Scottish Barony Register. A spokesman for the firm said: "It has been a long and complex sale but we can confirm today that the sale has now gone through. It has been purchased by Dr Stephan Roh and both he and his wife will become baron and baroness."