Did Lucian Freud disavow a nude self-portrait because he was embarrassed by it? That could be the case, according to the Guardian, which reports that after an unnamed Swiss collector bought the full-length painting at auction more than two decades ago, only to have the artist and his estate refute the painting’s authorship, three independent studies have now confirmed that the work is indeed an authentic work by Freud. The undated painting, titled Standing Male Nude, was sold at auction in 1997 in Geneva. According to the anonymous buyer, Freud himself telephoned and offered to pay twice the price just to have the self-portrait back in his own hands. Now, after years of…