"If She Knew" is a song by British R&B singer Lemar, released as the first single from his fourth album, The Reason. The song has been a further top 20 success for Lemar; it was C-listed on BBC Radio 1, entering the UK Singles Chart at #61 after just two full days of download sales, and then climbing to #14 upon the release of the physical CD. The following week the single fell to #19 but Radio 1 moved the track up to their B-list. In its fourth week, "If She Knew" dropped two places to #21.