Congrats to Jessica Simpson -- and to Maxwell Drew, who's now a big sister! She and fiance Eric Johnson have welcomed their second baby into the world.

Simpson gave birth to son Ace Knute Johnson today (June 30) via a scheduled C-section.

"Ace Knute (pronounced Ka-nute) Johnson has arrived! Mom and baby are doing great," Simpson's rep told Us Weekly. "Jessica, Eric and Maxwell are thrilled to welcome the new addition to their family."

Knute is said to honor Johnson's grandfather of the same name.

Simpson previously admitted -- somewhat accidentally -- that her pregnancy with her new son, Ace, was a lot tougher than the first go around with her daughter Maxwell. "The crazy thing is I never knew a wiener could make me nauseous," she giggled in March, before adding, "well, I guess I just told the world that I'm having a boy!"

Congrats to the happy family!