Ashlee Simpson: Son is amazing

Ashlee Simpson is enraptured by her four-year-old son.

The 28-year-old singer and actress shares Bronx Mowgli with ex-husband Pete Wentz.

The star loves being a mom to the fun-loving tot.

"[He's] smart, sweet and amazing. He's always funny," she told People magazine.

Ashlee starred in Chicago on Broadway in 2009 and is currently doing a revival of the stage production in Los Angeles. Bronx appears to love being around the glitz and glamour of showbusiness as it fuels his own creativity.

"He keeps you on your toes and he's got great stories and a great imagination," Ashlee explained. "When I was doing Chicago, he said he was making his own play about ninjas."

Bronx has also welcomed the latest addition to the family.

Ashlee's sister, Jessica Simpson, recently gave birth to four-week-old son, Ace Knute. The singer also shares 14-month-old daughter, Maxwell Drew, with fiancé Eric Johnson.

"Oh he loves it. He'll get it soon. Right now, he's like 'OK, Maxwell, come hang out with me! Let's go to your play room,'" Ashlee mused.

Ashlee is also a doting aunt.

The star helped to celebrate Ace's June 30th birth with a sweet gift she helped Bronx make for Jessica and Eric.

"There was this awesome thing that we made with Bronx," she said.

"It was like cool, vintage shirts all made into a blanket, so all these things that represented his mom and dad. So we made that all into a blanket. Just cute stuff - things that represent Eric, things that represent Jessica, and you take the little vintage shirts and jerseys and make [them] into a blanket."