Kevin Costner is raring to make his career comeback after lying low for a while, partly also because of the unrelenting pandemic that led to a series of lockdown.

An insider however is both amazed, and worried, that the actor is pushing himself to the limit - and then some - now that he's back at work on his blockbuster TV series, "Yellowstone."

"Kevin is one of the hardest working guys in Hollywood, and he's been crazy busy trying to catch up after the long delays due to lockdown," an insider reveals to OK!. Despite the fact that production for the fourth season has officially been completed, Costner, 66, who serves as both star and executive producer, is still engaging himself in a myriad of post-production work, effectively forgetting his own health and allegedly probably ignoring his own family.

"He's keeping tabs on the editing and overseeing other post-production work," spills the insider, who then added that the actor's grueling schedule is also affecting his home life with wife Christine Baumgartner and the three children they share, Cayden, 14, Hayes, 12, and Grace, 11. It can be recalled that "Field of Dreams" star married his second wife at his Colorado ranch outside Aspen back in 2004.

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Because of his work, Costner reportedly does not have a chance to spend some quality time with his family or visit his massive estate.

"They have an incredible 160-acre ranch in Aspen and a beachfront home in Santa Barbara [Calif.], but he hasn't been able to spend much time at either place," the insider revealed. "Kevin's a workhorse and deserves a lot of the credit forYellowstone's success, but he's running himself ragged!"

It remains to be seen how his hard work will ultimately pay off. What is clear though that his dedication to keep things moving despite the pandemic now meant that the season 4 of the show is now underway. In a way, the father-of-seven's tiring himself out had bear fruit. Season four of the hit series - which was dropped in 2018 - is set to premiere around the corner, by November 2021, to be exact.

Before the release of this season, Costner is also said to be slated for a live concert on October. The actor is actually the lead singer of an American country-rock band apart from being an actor and producer.

The band, aptly named Kevin Costner & Modern West, has been touring worldwide since 2007 and even already released a total of three albums so far. It was reported that the band will be going to the St. Augustine Amphitheatre on Oct. 25.The scheduled stop in Florida is just part of their bigger "Tales from Yellowstone 2021 Tour."