United Kingdom, Sept. 20 -- Penny Lancaster is the "oldest woman" Sir Rod Stewart has ever slept with.

The 54-year-old TV presenter has been married to the 80-year-old rocker for 18 years, having met him when she was just 27 and Penny revealed she is now the oldest woman he has ever been with.

She told Woman and Home magazine: "I'm the oldest person Rod's ever slept with - and that happened a long time ago.

"When I met him, the oldest woman he'd ever slept with would have been 30. Now he's the oldest man that I've slept with too!"

The couple have sons Alastair, 19, and Aiden, 14, and Penny admitted starting a family was the one thing that made her doubt their relationship.

She said: "My biggest burning desire was to have a family. I ...