Why is Rob McElhenney part of the MLB London Series?

It may not always be sunny in London, but producer and actor Rob McElhenney will make the transatlantic journey for the London Series of Major League Baseball's World Tour.

McElhenney, known for his role as Mac in the FX comedy series "It's Always Sunny in Philadelphia," will throw the ceremonial first pitch for the second game of the London Series.

The MLB World Tour is part of the league's plan to expand globally, which has the intention of playing up to 24 international games through the 2026 season. The two-game series in London will feature the Philadelphia Phillies and New York Mets at London Stadium on June 8-9.

McElhenney will celebrate the occasion in the London Series due to his unique friendship with Philadelphia legend Chase Utley, who is the MLB ambassador in Europe.

Chase Utley or Bryce Harper? Rob McElhenney will choose at MLB London Series

Mac, McElhenney's character in "It's Always Sunny in Philadelphia," writes childlike letters to Utley. The letters transcended the show and spilled into reality, as McElhenney and Utley ultimately wound up developing a friendship.

"Dear Chase, I feel like I can call you Chase because you and me are so alike," Mac's letter reads. "I would love to meet you someday, it would be great to have a catch. I know I can't throw as fast as you but I think you would be impressed with my speed. I love your hair, you run fast. Did you have a good relationship with your father? Me neither."

McElhenney finally got the opportunity to play catch with Utley in 2019, when he tossed the first pitch to his baseball idol. He also caught a ball from Utley during the Phillies' World Series appearance in 2022.

At the London Series, McElhenney will have to choose between Utley, his long-time love, and Bryce Harper, the new Phillies superstar.

In a promotional video for the London Series, McElhenney begins writing letters to new Phillies superstar Bryce Harper. Utley learns of McElhenney's betrayal when Harper asks him what he should do about obsessive letters from a fan. Utley then gives McElhenney an ultimatum: would he rather play a game of catch with Utley or with Harper?

The answer, of course, won't be revealed until the pregame festivities on Sunday, June 9.