President Obama congratulates Phelps on Twitter during NBC’s Olympics broadcast

It seems even the president of the United States is watching the London Olympics on tape delay.

"Congrats to Michael Phelps for breaking the all-time Olympic medal record," President Barack Obama tweeted late Tuesday, after the celebrated American swimmer won his record 19th. "You've made your country proud."

The president's tweet (signed "-bo" to denote it was from him and not a member of his re-election campaign) came during NBC's prime-time broadcast of an event that happened earlier in the day—and some of Obama's 18 million followers on Twitter decided to voice their displeasure with the network to the commander in chief.

"Uh, that happened hours ago Prez," Thomas Attila Lewis wrote in response. "@NBC is embarrassing our country."

[Also see: Yahoo's complete coverage of the 2012 London Olympics]

Phelps, though, appreciated the message, however delayed.

"Thank you Mr. President!!" Phelps tweeted at 3:02 a.m. local time. "It's an honor representing the #USA!! The best country in the world!!"

According to White House press secretary Jay Carney, Obama followed up the congratulatory tweet with a phone call on Wednesday from a campaign stop in Mansfield, Ohio.

"The greatest Olympian ever," the president told Phelps, according to Carney. "We couldn't be prouder!"