(Cover) - EN Showbiz - Rod Stewart and Penny Lancaster used in vitro fertilisation (IVF) to get pregnant with their second child together.

The couple announced they are expecting a baby last month, which will be the rockers eighth child. The 65-year-old and his 39-year-old wife already have four-year-old son Alastair together, and have been trying to give him a brother or sister for two years.

They sought medical help when Penny failed to fall pregnant, eventually discovering she was having a baby after her third round of treatment.

Our sons happiness made all the IVF treatments worthwhile, she told the British edition of Hello! magazine. I couldnt believe it. I burst into tears. I called Rod when I was still sobbing. Rod said, Im in the middle of a restaurant in Russia, crying. I kept pinching myself. Neither of us could believe it.

Rod added undergoing IVF was gruelling, but the couple coped by sticking together. He tried to support Penny as much as possible, and they both knew they were doing the right thing.

IVF can be stressful, especially for the woman with all the hormone injections and procedures. I said to Penny, Dont worry, well just keep trying, he explained.

Penny and Rod approached fertility specialists in both American and Britain for help. It was found that Penny had high levels of mercury in her body, so she was told to stop eating so much fish.

A homeopathic doctor told me my mercury levels were really high, off the scale. I do love fish, and I thought it was healthy without understanding the high mercury levels that fish like tuna, swordfish and halibut can contain. My doctor said it was unhealthy to have so much mercury in my body, and also for conceiving babies, Penny explained.

After two months of not eating fish, my mercury levels dropped by half, which is scary - I had no idea what the fish had been doing to my body.

The baby is due in early 2011. (C) Cover Media