Carrie Underwood celebrates son Isaiah's 7th birthday: 'He has the biggest heart'

It's lucky number seven for Carrie Underwood's oldest son!

The country music superstar and her husband, Mike Fisher, celebrated the seventh birthday of their son Isaiah on Sunday.

Underwood commemorated the occasion with a celebratory post on Instagram showing that Isaiah had a "Star Wars"-themed birthday party at a skating rink with his friends. The cake showed Isaiah's name written in bold red lettering with a Kylo Ren mask adorning the top as well as a decorative "7" to mark his latest milestone.

But alongside the fun depicted in the photos, the "Jesus Take the Wheel" singer took a moment to reflect on her son's character.

"It has been so much fun to see this little dude grow! He has the biggest heart and the brightest smile," she wrote in the caption, praising her firstborn son's "strong and pure" faith. "He is an old soul with a vintage style…wise beyond his years."

"I am so blessed to be his mom and I can't wait to see where God leads him in the years to come," she concluded. "Happy birthday, monkey! We love you!"

Underwood and Fisher, who married in July 2010, are also parents to 3-year-old son Jacob.