The oil painting “Girl Reading a Letter at an Open Window” by Johannes Vermeer underwent a major restoration completed in 2021. Thereby, a painting of cupid on the back wall, which had been overpainted after Vermeer’s death, was revealed. The discovery of this painting within a painting changed not only the composition, but also the semantic interpretation of the artwork. Many scholars argue that the display of cupid reveals the nature of the letter as a love letter. We performed eye tracking and a visual saliency study of digital copies of the painting to investigate this semantic change. Thus, we defined five areas of interest: foreground, reader, window, letter, and cupid/wall. While we monitored their eye movements, 67 lay people freely viewed (A) the painting with the blank back wall and (B) the restored version with the painting of cupid (balanced study design) for 10 seconds. Comparing both versions, the painting of cupid drew visual attention (measured by total fixation duration) mainly from the letter. Additionally, we performed an objective visual saliency analysis. Visual saliency turned out to be rather similar between both versions. In sum, participants paid less visual attention to the letter in the cupid version (eye tracking) while the visual saliency was not significantly different between both versions (saliency). Our results are in line with the interpretation that the display of cupid removes the letters’ ambiguity. We speculate that the change of visual attention is mainly driven by semantic features and not by visual image properties.