(IDEX Online) - Pop icon Beyonce is to become the face of Tiffany & Co, along with rapper husband Jay-Z, in a deal revealed yesterday by Harper's Bazaar.The singer appears on the cover of the magazine's Tiffany-sponsored September issue, wearing a +21-ct Tiffany diamond. She is also featured inside in an interview and photoshoot.The appointment of the superstar couple follows the announcement in June of three global brand ambassadors: Diana Ross's daughter, Tracee Ellis Ross; Anya Taylor-Joy (star of Netflix miniseries The Queen's Gambit) and Eileen (Ailing) Gu, 17, the champion freestyle skier.Tiffany was acquired by the French luxury conglomerate LVMH in on-off-on-again $16.2bn buyout.Its new executive vice-president, Alexandre Arnault - 29-year-old son of LVMH boss Bernard Arnault - has pledged to "focus on advertising campaigns and luring young customers".A recent poster campaign headlined Not your mother's Tiffany, showing grungy young women with attitude, was condemned on social media as disgusting, disrespectful and ageist.