Alastair Stewart and Sir Rod Stewart.Photo:Dave Benett/Getty

alastair stewart rod stewart son london 10 12 23

Dave Benett/Getty

Rod Stewart’s son is all grown up!

On Tuesday, the rock legend, 78, and wife Penny Lancaster, 52, spent the day with son Alastair celebrating his 18th birthday.

A photo from the day shows the couple lounging on the couch with their son. Later, they all get done up as they step out to continue the festivities out on the town.

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Penny Lancaster and Rod Stewart with son Alastair on his 18th birthday.Penny Lancaster/Instagram

penny lancaster son alastair 18th birthday rod stewart instagram

Penny Lancaster/Instagram

Stewart appeared on the cover of the November issue ofHaute Living, where he praised his kids and their accomplishments.

“I don’t think I’m as strict with my kids as my mom and dad —especiallymy dad — were,” Stewart told the outlet. “I’m very lenient with them. None have gotten into any serious trouble. A couple dabbled with drugs, but that’s all done now. I’m very proud of them all.”

He also added that when he’s on the road he misses his family “so much,” and that his loved ones are “a wonderful luxury” when he returns home.

Stewart family.Kimberly Stewart/ Instagram

Rod Stewart Is Surrounded By Kids and Grandkids in Beautiful Family Photo from Spain: ‘La Familia’

Kimberly Stewart/ Instagram

According toHaute Living, Stewart already has eight grandchildren.

source: people.com