The quintessential flower child of the 1960's, 70's, 80', 90's, and on past the millenium.
Although you can read that Melanie's biggest hit, "Brand New Key", was on her own record label, twenty-five years later she spoke rather negatively about the background vocals added in studio. So from that comment (plus the year the record was released), it looks like that was her last big hit before she went to her own label.
But in any case, at the concert she said time heals all wounds and even asked the audience to add the extra parts. After all, studio background or not, the song did sell more than two million copies.