Sen. John McCain (R-Ariz.) weighed in on the shake-up of hosts at ABC's "This Week" via Twitter Monday.

Sunday was the debut show for Christiane Amanpour, the former international correspondent for CNN who replaced eight-year host George Stephanopoulos, who is now a co-host of "Good Morning America."

ABC's White House correspondent Jake Tapper filled in on the leading Sunday morning show for four months between the two.

McCain, noting the transition, tweeted:

Anyone else miss @jaketapper yesterday?

July 25 was Tapper's last "This Week" broadcast. 

"There's a tremendous amount of thought and preparation when it comes to interviews, when it comes to the roundtables, when it comes to booking guests," Tapper said, commenting on his time as anchor. "Most of the work is before the show — I think I wasn't necessarily prepared for that." 

Meanwhile, reviews of Amanpour's first show have been mixed. Many critics noted Sunday that her aggressive, "on-the-ground" sensibility is unorthodox for a political talk show host.

"I'm sure she'll do a great job and doesn't need any advice from me,” Tapper has said of her. “She has a very celebrated career, and I'm sure she'll do fantastically."