Dax Shepard is in recovery after undergoing further shoulder surgery following a recent biking accident.

The Parenthood star had to have a metal plate inserted in his left shoulder after suffering multiple broken bones in a motorcycle crash last summer, and he unknowingly harmed the hardware in late 2020 after swerving on his electric bicycle to avoid a car, causing him to collide with a parked truck.

He tried to ignore the pain for as long as possible, but when his shoulder swelled up while he was on location in Utah for Top Gear America last month, he finally got it checked out and learned he needed another operation.

"So I went on a Wednesday morning, got it X-rayed, found out that the bolts had come out of one side of the plate, and the plate was raised quite a bit," Shepard explained on Thursday's episode of his Armchair Expert podcast.

He tried to delay the surgery until he finished shooting Top Gear in May, but was warned his injury was like a "grenade", so he ended up having the operation just two days later.

However, the procedure was more serious than initially thought, as his doctor had to take a bone graft out of his hip to put in his shoulder, where the surgeon discovered he may have an infection.

Shepard has now been left with a port in his arm to administer "really heavy antibiotics" until the issue is resolved, while he's also got swelling in the area of the bone graft.

"My hip is insane..., (it) looks like I have a watermelon on my hip," he shared. "The shoulder's totally fine, it's really just the hip that is brutal."

The operation comes almost six months after Shepard went public with his sobriety relapse, after getting hooked on pain medication following his last shoulder surgery, and as a result of his past substance abuse, his actress wife, Kristen Bell, has taken charge of his prescription medications to ensure he doesn't slip up again.

"The doctor and Kristen talked at length about what the game plan was for medicine, and then obviously I'm getting drug tested as soon as the prescription is over so that we know there's no way I went and got my own prescription," he said. "I'm not allowed to get a prescription from the doctor (himself). Those are the precautions."