Justin Hartley suffered a painful injury during quarantine.

The “This Is Us” actor appears as a guest on Tuesday’s “Ellen DeGeneres Show” and tells the host about his plans to use the quarantine to get fit.

Hartley jokes he also planned to learn a foreign language and how to play an instrument during lockdown, but his body had other ideas.

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“I was working out and I ended up doing something really ridiculous. I tore my bicep off my arm. It was nasty. The tendon that holds it to the bone came off. It sounded like someone ripped your shirt. It was bad.

“[The exercise] was something that I made up. It was something that I shouldn’t have done. It was like a bicep curl, but I think I jerked the weight or maybe it was too much weight.”

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Hartley continues, “I heard it. I think I was in shock, but it felt like… the way I would describe it is, I stopped because I heard it. It was an awful sound. I felt like a little grain of sand [near my bicep]. Then it turned into like a pea, then a marble, then a golf ball, then a tennis ball, then a softball, and then a watermelon. It just felt like it was huge, like a human head was in there.”

The actor says doctors “put it back” after cutting him open, telling DeGeneres it took him about three months to heal but he’s now able to lift weights and everything again.