It's a boy for 'DWTS' pros Maksim Chmerkovskiy and Peta Murgatroyd

The new year is off to a swinging start for longtime Dancing With the Stars pros Maksim Chmerkovskiy and Peta Murgatroyd.

The dancers, who became engaged in December 2015, are now the proud parents of a boy, Shai Aleksander Chmerkovskiy, born at 5:34 a.m. PT Wednesday morning, according to Maks' Twitter feed.

Fans and the media were tipped off Tuesday as to Shai's imminent arrival when Maks' younger brother and reigning DWTS champ Val had to back out of a tour date in Richmond, Va., in order to get back to California to be there for the birth of his nephew. "My [future] sister-in-law Peta Murgatroyd is literally delivering the baby as soon as I'm done with this video, hopefully," he explained in a taped message.

Chmerkovskiy, who turns 37 later this month, and Murgatroyd, 30, first met while working on Broadway's Burn the Floor in 2009 and told People they had felt immediate chemistry but didn't act on it since they were both with other people at the time. He was engaged to fellow Ukrainian-born DWTS pro Karina Smirnoff and she was seeing Australian Damian Whitewood, who danced in that country's version of the show.

They finally got together in 2012, broke up in 2013, then reunited in 2014. He proposed onstage during a performance in Miami on Dec. 5, 2015.

Between the two of them, they've won DWTS four times. Three of those mirrorball trophies belong to Murgatroyd, who's won with model Nyle DiMarco (Season 22), Army veteran-turned-soap-opera actor J.R. Martinez (Season 13) and NFL player Donald Driver (Season 14). Chmerkovskiy's win came in Season 18 with Olympic ice dancer Meryl Davis.