LOS ANGELES (SS)- Avril Lavigne is getting married. The singer is engaged to Nickelback frontman Chad Kroeger. The pair have been quietly together for six months. 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 told People magazine.