Sen. Jeff Flake, R-Ariz., said he had a “nice visit” with Sen. John McCain, who is recovering from complications related to his chemotherapy treatments for brain cancer.

“Had a nice visit with @SenJohnMcCain today,” Flake tweeted about his fellow Arizonian. “He's working hard and gaining strength.”

The 81-year-old Republican senator was hospitalized at Walter Reed National Military Medical in Bethesda, Md., in December for a viral infection and side effects related his chemotherapy treatments. Before the end of 2017 he returned to his home state of Arizona from Washington, D.C., and has been recovering there, attending physical therapy sessions, ever since.

While his Senate office has not provided an official update on his health since mid-December, his daughter and co-host of "The View," Meghan McCain, said earlier this week there is “a very high likelihood that he will come back to D.C. at some point." She said that the 2018 flu season played a factor in McCain's delayed return, even as his Senate colleagues voted on another short-term spending deal to end another brief government shutdown.

The younger McCain told CNN on Saturday that he is doing “really good, all things considered.”

Sen. McCain was diagnosed with primary glioblastoma, an aggressive form of brain cancer, last summer and has been undergoing chemotherapy since.