United Kingdom, March 31 -- Channing Tatum has been "mentally up and down" more than any other time in his life while dealing with a shoulder injury.

The 45-year-old actor has gone through "the lowest of the lows" as he recovers from surgery, which he underwent earlier this year after separating his shoulder, but he admitted it is a "good day", because he has been given the "green light" from a doctor to train again.

Tatum showed fans his surgery scar in an Instagram video, and he said in the clip: "The scar is actually healing up pretty nice.

"I'm getting some mobility back. It's atrophied so much though.

"I feel like a toddler in the gym.

"The good news is though, the doctor finally gave me the green light, so I can train.

"It's a...