Rob Gronkowski learns how truly painful it is to give birth on Game On!

NFL superstar Rob Gronkowski learned how painful it is to give birth on Thursday’s episode of Game On!

In one segment of the CBS game show, teams showed photos of themselves as kids, and talked about famous athletes with big families.

That led show host Keegan-Michael Key, 49, to ask Rob, 31, if he thought he would be able to handle delivering a child.

‘Of course!’ said the three-time Super Bowl champ, eager to prove his strength. ‘I mean, a broken MCL, four forearm surgeries, ankle surgery, four back surgeries… what’s a baby?’

To end Rob’s boasting, Keegan-Michael brought out a machine that ‘allows men to experience and empathize with the excruciating pain of childbirth.’

Rob lay down on a stretcher as attendants placed electrodes on his abdomen, preparing to give him shocks that resembled labor pains.

Keegan-Michael promised he’d give Rob’s team a point if he could handle it.

Comedians Ian Karmel, 35, and Bobby Lee, 48, stood nearby with ice chips and moral support as the dial on the machine was turned up to one.

Rob stopped laughing.

‘I’m having triplets!’ he cried, trying to look stoic and failing.

‘You look so beautiful!’ Ian praised him, doing Lamaze breaths as Bobby wiped Rob’s face. ‘Go ahead and breathe for us!’

‘He’s coming!’ Rob yelled, as the machine went up to five. ‘He’s so close!’

When the dial hit 10, Rob writhed in pain, laughing as Ian yelled, ‘Hang in there! Hang in there!’

‘Turn it off,’ Keegan-Michael told his staff, awarding Team Gronk the point.

‘Gronk!’ Ian called, cradling Bobby in his arms like a baby.

‘He’s beautiful!’ Gronk said, looking at his ‘child.’ ‘I love you!’

Rob returned to his seat in triumph, cheering, ‘Yes! I knew I could have a baby!’

Wednesday’s episode of Game On! Featured a guest appearance by comedic actor Ken Jeong, 51, who joined Venus Williams, 40, and Ian on Team Venus.

Rob’s Team Gronk was comprised of Bobby and guest star Tiki Barber, 45, the New York Giants’ all-time leading rusher.

As the game began, Keegan-Michael pointed out that Rob owned a horse, which the athlete confirmed and said was named Gronkowski.

He was shown at the Kentucky Derby with Tampa Bay Buccaneers teammate Tom Brady, 42, both of them dressed in unusual outfits.

‘This looks like Tom Brady ran into his eccentric Danish friend from college, who’s now a YouTube star,’ Keegan-Michael joked.

The first challenge, Derby Daze, found teams racing stuffed horses around a track, using only the motion of their bodies pumping up and down to make them go.

Bobby, who rode ‘Leebiscuit,’ and Ian, on ‘Pony Soprano,’ were quickly disqualified for getting off their horses and carrying the animals toward the finish line.

Rob looked like he might win with his horse ‘Roberto,’ but at the last minute, Venus overtook him on her steed, ‘War Horse,’ giving her team the lead.

Challenge two asked the teams to decide which of three top athletes had the most children.

Team Venus won again by guessing that it was Secretariat, the late Triple Crown-winning horse, who sired 453 ponies.

Heavyweight boxer George Foreman, 71, came second with 10 kids, while Indianapolis Colts quarterback Philip Rivers, 38, had nine.

The third challenge found Rob, Venus, and Keegan-Michael competing to be the best monster truck driver.

All three of them drove around a Monster Jam track, earning points for their time, technique and style.

Team Venus won their third round by correctly intuiting that Venus would place first, followed by Rob and Keegan-Michael.

During his lap, Keegan-Michael dramatically flipped his truck, though he was not injured.

‘There’s two types of Monster Jam drivers,’ monster truck legend Tom Meents reassured the man. ‘Those who will roll over, and those who have rolled over.’

Challenge four required the teams to match athletes to their hidden talents.

Team Gronk easily won the round, accurately guessing that former NFL quarterback Eli Manning, 39, was a juggler, Los Angeles Lakers star Rajon Rando, 34, was good at Connect Four, and onetime NHL center Mike Fisher, 40, could fit a tennis ball in his mouth.

Asked if she’d ever eaten a tennis ball, Venus said, ‘You’ve got to make your opponent eat the ball.’

Rob then successfully fit a tennis ball in his mouth, after which Bobby shoved it in his.

The show’s final challenge, Arctic Assault, had teams climb a platform, then jump down into an icy obstacle course.

As they scaled its cliff, slid into its slush pit, and dove into its freezing pool, the other team could answer sports-related questions, aiming to complete as many as they could.

Rob and Bobby did well in their attempt, though Bobby joked that he died and was reborn as a phoenix.

Ian struggled to mount the slippery slide, but had the crowd cheering for him until he finished.

‘I’m winded,’ cracked Ken, who’d done nothing the whole episode. ‘It was a team effort.’

In the final tally, Team Venus won the game, earning 21 points to Team Gronk’s 16 points.

As punishment, Rob had to do something he hated: sing a karaoke cover of Gloria Gaynor’s I Will Survive, which he did off-key until the credits rolled.

Game On! returns next week on CBS.