Carpenter selected the composition for the duo's third single and included it on the LP "Close to You". Released in late summer 1970, the single featured Karen's lead vocals and the overdubbed harmonies of both siblings. Following their hit "(They Long to Be) Close to You" onto the charts, "We've Only Just Begun" hit No. 1 on the Cash Box singles chart and No. 2 on the U.S. "Billboard" Hot 100 behind The Jackson 5's "I'll Be There" and The Partridge Family's "I Think I Love You", becoming the pair's second million-selling gold single. It was considered by both Karen and Richard to be their signature song. According to "The Billboard Book of Top 40 Hits" (6th edition), on the U.S. Adult Contemporary singles chart, it was the duo's best-performing tune, lasting seven weeks at No. 1 (beating the six-week stay at the top of "Close to You"). The song also helped them to win two Grammy Awards in 1971: for the Best New Artist (The Carpenters) and Best Contemporary Performance by a Duo, Group, or Chorus ("Close to You").