Lee Hadwin has no artistic ability. Unless he’s asleep.

Once he conks out, the self-dubbed “Sleep Artist” creates celebrity portraits, classical nudes and stunning abstracts that he sells for thousands of dollars.

“I just can’t draw when I’m awake,” said Hadwin, 44, who got terrible grades in high-school art class in his native Wales.

Yet when asleep, he is able to control the images he puts down. He just doesn’t remember doing it.

It began when Hadwin was just 4 years old. He started scribbling on the walls and floor of his bedroom after he fell asleep.

“I would go downstairs at night and draw under the staircase,” he recalled.

His parents took him to doctors after a few years of his unusual behavior, but they were told he was just sleepwalking — with an artistic flair.

“My mind is in a sleeping state and my body is in a waking state,” Hadwin said.

When he was 15, his overnight etchings resulted in three portraits of Marilyn Monroe.

“Only after I drew them, that’s when I thought, ‘Something strange is going on,’ ” he said.

But it wasn’t until the early 2000s, when he was asked to show his work at a library, that he gained attention as an artist. A local newspaper did a story on the show, and it was picked up by the British national media.

“My life changed overnight,” he said. “It went from a local library doing five pictures in frames to this global recognition in the art world.”

Hadwin has been examined by sleep experts from Scotland to Japan who documented his actions but gave little explanation for how he gains an artistic ability that disappears with the sun.

Sometimes, he’ll get out of bed two or three times in a single night. Other times, a few weeks might pass without him picking up a pencil.

The London resident says he fully embraced his somnambulant skills about 10 years ago and started stashing art supplies under his bed to be ready for his inspirations.

“I’ve done it since I was 4 years old, so for me I don’t know any different,” he said.

But he admits it’s difficult to explain his nocturnal exploits to others, including his husband, Clinton. “It took him about eight months to believe it,” Hadwin said.

Several pieces, including two Marilyns, have sold for thousands of dollars. The most he got was about $125,000. He donates a portion of each sale to charities like Amnesty International.

Hadwin didn’t always consider himself an artist, and many art critics say he still shouldn’t. But he shrugs off negative reviews.

“I take it with a pinch of salt,” he said. “My art is what it’s worth.”