Shawn Mendes Performs 'Mercy' & 'Treat You Better' on 'Saturday Night Live'

Shawn Mendes
Will Heath/NBC

Shawn Mendes performs on Saturday Night Live on Dec. 3, 2016.

While Emma Stone is a superstar of young Hollywood at age 28, her Saturday Night Live companion this weekend was even younger. Shawn Mendes made his SNL debut at just age 18 on Saturday night, as the musical guest alongside host Stone.

He started things off at the piano with "Mercy," the latest single from his second album Illuminate, which debuted at No. 1 on the Billboard 200 back in September. Blue and white lights lit the stage as Mendes made his way from behind the keys to center stage after the first chorus, earnestly emoting his way through the midtempo number.

For his second song, he chose "Treat You Better," the first single from Illuminate. While his fans are very familiar with the song -- which hit the Billboard Hot 100 top 10 -- Mendes took some liberties with the melody and showed off some very elastic vocal skills.

Watch both performances below: