(Yahoo!) - Baby boy joy!

Just one day after welcoming her second child into the world, Ivanka Trump and hubby Jared Kushner were ready to show the little guy off.

The 31-year-old daughter of mogul Donald Trump, posted a photo of her newborn son in her arms at the hospital along with the baby's birth announcement on her Tumblr account.

"With love we welcome our son, Joseph Frederick Kushner," she wrote, revealing he was born at 9:54 p.m. birth on Monday, October 14.

Joseph Frederick, who joins big sis Arabella, is named after both of his parents' paternal grandfathers.

"Jared’s grandfather, Joseph, was a rock," Trump writes. "His indomitable spirit, his sense of family, and his work ethic are the values we hope to hand down to our son. My grandfather,Frederick, was a builder not just of tens of thousands of homes throughout this city, but of a tight-knit family that honors to this day the traditions he established."

Donald Jr. tweeted his congrats:

Proud grandpa, The Donald, also took to Twitter to announce his excitement over the news:

But they weren't the only family members excited about the new arrival. Ivanka also shared an adorable photo of 2-year-old Arabella holding her new brother, with the caption, "such a proud big sister!"

Wish the family congrats!