AceShowbiz - Tom Selleck appeared to have quietly undergone a surgery. The actor portraying NYPD Police Commissioner Frank Reagan on "Blue Bloods" was spotted with scars on both of his knees as he seemingly had trouble walking.

In a series of photos that were recently obtained and published by In Touch Weekly, it could be seen that the 79-year-old actor was out and about in Thousand Oaks, California on July 17. He was photographed making his way out of a gym apparently after doing his workout routine.

Tom was caught on camera walking alone while leaving the gym, seemingly heading to his car in the parking lot. At that time, the actor, who showed a stern facial expression, had apparent vertical surgery scars on his knees.

According to the media outlet, Tom "visibly had trouble walking." As he walked towards his vehicle, he reportedly "stopped in front of his truck and held onto the hood of his car." He "then focused on breathing and held onto his car until he got into the driver's seat."

The outlet also claimed that the former "Las Vegas" star drove to a fast food restaurant to grab a drink following his gym session. He allegedly "stopped at a McDonald's drive-thru for a soda."

For his workout session, Tom went with an all-black sporty ensemble. He opted to wear a short-sleeved black tee and a pair of matching shorts. He completed the look with a pair of matching socks and matching sneakers. To accessorize himself, he put on a silver wrist watch. In addition, he embraced his gray hair and beard.

Tom has not publicly talked about undergoing a bilateral knee replacement surgery or a double knee replacement. Previously, it was reported that he was suffering from "a secret medical crisis that has forced him to use a stunt double while filming 'Blue Bloods'."

Tom allegedly was "in a lot of pain and agony" and had to "learn techniques to alleviate" his pain with doctors. In response, his representative shut down the claim, insisting that the actor was "fit and vigorous."