“He’s doing well, in good spirits and walking around a little more in his room,” a friend said of the “America’s Got Talent” star, who had a metal rod inserted in his back during a six-hour surgery Saturday after falling off a high-speed electric bike.

“He’s been doing more work and this morning was playing jokes on [girlfriend] Lauren [Silverman] and some of his friends,” the source said of Cowell, 60.

He’s “just being silly, joking around,” the friend said. “He knows he had a lucky escape and is very grateful for that and the medical teams, who have been incredible.”

Cowell broke his back in three places — coming within an inch of cutting his spine and facing possible paralysis — while showing off his fancy new $20,000 high-powered e-bike to his 6-year-old son Eric and 14-year-old stepson Adam, outside his Malibu, Calif., pad, friends have said.

The bike suddenly did a wheelie, sending Cowell flying to the ground.

The star tweeted Sunday, “Some good advice . . . If you buy an electric trail bike, read the manual before you ride it for the first time.”

The bike he was on at the time goes so fast, up to 60 mph, that it’s been banned from the open road in the UK.

Cowell faces weeks of rehabilitation and will miss the first resumed live “AGT” shows on Tuesday and Wednesday night.

But the source said of the star, “Being the workaholic that he is, he’s already working and taking calls.”

Still, “He knows he’s got to take it easy.”