Andrew James Tierney (born 20 June 1974) is a member of Human Nature.Andrew and brother Mike are the main songwriters of the group, co-writing the singles Got It Goin' On, Telling Everybody, Don't Say Goodbye, Whisper Your Name, Be There With You, When We Were Young (with the rest of the band), Always Be With You and Don't Come Back. Andrew is known for his high falsetto.Andrew is married to Heather Tierney, the older sister of Andrea Tierney who is married to Andrew's brother Mike Tierney.