Eric Trump and his wife are expecting their first baby

Eric and Lara Trump shared exciting news with PEOPLE on Monday -- they're expecting their first child!

Donald Trump's second-oldest son, who is 33 years old, told the magazine it was "pretty cool" news to receive on his birthday, which was Jan. 6.

Lara Trump, also 33, is a former INSIDE EDITION producer who is now involved with multiple animal charities.

She told PEOPLE that now she's in her second trimester and she's feeling great.

"It surprised me, because I'm a very active person, and until the fatigue hit, I didn't believe it would actually happen to me," she said. "It really affected me. But I'm feeling really good now."

The baby, which the couple announced is a boy, will be President Trump's ninth grandchild.

Eric's older brother, Donald Trump Jr., has five kids with his wife Vanessa. His sister Ivanka has three kids with her husband, Jared Kushner.

The couple is currently brainstorming names.

"We really loved the name Charlie, but we'd already named our dog that, so it's out," Eric told PEOPLE.

"We sort of screwed ourselves over there," Lara added.

She said that she's not nervous about becoming a parent at all, and that's she's always wanted kids some day.

"Eric's going to be an amazing dad," Lara told PEOPLE. "The nieces and nephews love hanging with him. He's the cool uncle. He's watched 'Frozen' many times."

The couple, who married at Mar-A-Lago in 2014, said the pregnancy was hard to keep secret.

"Eric's dad was so excited," Lara told PEOPLE. "We were worried he'd blurt it out at a press conference."

See more photos of Eric:

[H/T PEOPLE]