The millionaire art dealer and his new partner have been celebrating her 50th birthday by visiting art museums and dining in lavish restaurants in the country.
Trinny posted a photograph of her and Saatchi on her Instagram account having breakfast in Madrid, along with the caption, "Half a century".
In another snap, the TV star is seen wearing a new black and white top and posts the message, "Gorgeous present".
She also shared photographs of a visit to a gallery and a snap of her daughter Lyla, 10, her child with ex-husband Johnnie Elichaoff.