AVRIL Lavigne and Nickelback frontman Chad Kroeger's relationship has been so quiet that few even knew they were dating.
Now, after a six-month courtship, the Canadian rockers are engaged to be married, Lavigne's rep tells PEOPLE exclusively.
Lavigne, 27, and Kroeger, 37, first got together in February to co-write a song for Lavigne's upcoming fifth studio album.
"A romantic relationship blossomed as they spent time writing together," a Lavigne pal tells PEOPLE.
Read more at People.