Backstreet Boys: "What Makes You Different (Makes You Beautiful)".

One Direction: "What Makes You Beautiful".

Backstreet Boys: "It's Gotta Be You".

One Direction: "Gotta Be You".

Backstreet Boys: "More Than That".

One Direction: "More Than This".

Backstreet Boys: "I Want It That Way".

One Direction: "I Want".

Backstreet Boys: "Love Will Keep You Up All Night".

One Direction: "Up All Night".

Hmmmmmmmmmmmm

 (This is not an attack on One Direction FYI, I happen to like both)