Duke and Giuliana Rancic Credit: Chris Haston/E! Entertainment/NBCU Photo Bank via Getty Images

Gather round, kids! Giuliana and Bill Rancic's 4-year-old son, Duke, is the life of the party in their Chicago hometown. The Fashion Police cohost gushed over her little guy's passion for singing exclusively with Us Weekly during a Thursday, May 26 chat.

"He loves to sing. He's enjoying a lot of that lately. His favorite song is 'Three Little Birds' by Bob Marley. He knows every word to the song," the proud mom, 41, tells Us. "I mean some of the moms of the neighborhood come over and think it's so funny. We have a karaoke machine and he takes it very seriously. He sings every word. It's the cutest thing."

"He's very energetic and full of life," she adds. "He's certainly not shy."

Giuliana and Bill, 45, relocated from L.A. to the Windy Cindy (in Bill's home state) last year, and welcomed Duke via surrogate in August 2012. The former E! News host, who has been open about her infertility struggles in the past, hopes that they will expand their family one day. (In 2014, the same surrogate suffered a miscarriage with their second child.)

"We just kind of started having the conversation again and obviously I went through infertility struggles and then breast cancer. It's something that has to take a lot of thought on our part because there are a lot of moving parts involved," she told Us.

"We are really enjoying our time with Duke and our new life in Chicago, so now that we are really settled in and things are great, we're thinking about possibly trying for another one. We have not, to be quite honest, gone down the road yet. But hopefully one day soon we will have some good news to report," she continued. "I would love more kids, for sure. Bill and I would both love to grow our family even more. We just love Duke so much and to be able to give him a brother or sister would be wonderful. Hopefully God will bless us with that. As Bill always says, 'It's up to the big man!'"

The TV personality is focusing on other aspects of her life for now. She's busy with her Xo, G wine collection, HSN clothing line and taking part in Red Nose Day, which she has partnered on with Walgreens, the exclusive Red Nose Day retail partner. The campaign helps raise awareness and donations for kids fighting poverty.

"This is a cause I would have been involved with before I became a mom, but certainly it has a different meaning now that I am a mom," she told Us, adding that she bought Duke a red nose to participate. "You start planting that seed with children at a young age and they hopefully grow up to give back and pay it forward."

NBC airs its second annual Red Nose Day Special on Thursday, May 26, at 9 p.m. ET.

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