Deryck Whibley

Deryck Whibley

Avril Lavigne's ex-husband has legally dropped her last name.

Deryck Whibley, who changed his name to Deryck Lavigne Whibley after he married the 'Hello Kitty' hitmaker in 2006, filed court documents to switch back to his original moniker last November, four years after their divorce in 2010, and a judge has now signed off on the request, according to gossip website TMZ.com.

The Sum 41 star and Avril - who is now married to Nickelback frontman Chad Kroeger - are still on good terms and the 29-year-old beauty praised him for seeking help and encouraged him to "stay strong" after he opened up about his struggles with alcohol addiction last month.

The 34-year-old rocker is now on the road to recovery and he recently assured his fans that he is doing well.

He wrote on his official website: "My days are quite full, but I work on getting better every day. I have doctor check ups often, and I've had so many needle pricks in the past few months, that all the veins in my arms are dead. I do a lot of physical therapy because my legs have gotten very numb from my kneads down. I'm only now starting to be able to get up and walk on my own, but it's still very painful."

The Canadian star previously admitted he had been "scared straight" after he woke up in an intensive care unit.

Alongside pictures of himself looking thin and frail, he wrote: "The reason I got so sick is from all the hard boozing I've been doing over the years. It finally caught up to me."

He added: "I had no idea where I was. I was so freaked out. My liver and kidneys collapsed on me. Needless to say it scared me straight. I finally realised I can't drink anymore. If I have one drink the docs say I will die (sic)."