Mookie Betts' blockbuster move from the Boston Red Sox to Los Angeles Dodgers was confirmed on Monday, while David Price is making the same switch.
An All-Star in each of the past four seasons and the 2018 American League MVP, Betts was traded to the Dodgers.
The outfielder and Price, plus cash considerations, are heading to the Dodgers in exchange for Alex Verdugo, Jeter Downs and Connor Wong.
The move was confirmed by both teams on Monday.
"In trading a great player, a beloved player, we recognise how incredibly difficult this is for fans who fully understand just how special Mookie is," Red Sox principal owner John W. Henry said in a statement.
"While the organisation in its entirety very much wanted to see Mookie in a Red Sox uniform for the length of his career, we believe in this decision as we are responsible and accountable for both the present and the future of the Red Sox. We thank Mookie for his incredible contributions, both on and off the field.
"David's arrival in Boston paved the way for a historic chapter for the Red Sox. His presence at the top of our rotation was critical to winning three consecutive division championships, and his 2018 postseason performance put both his talent and tenacity on full display.
"We appreciate what both Mookie and David brought to our club, and are grateful that they will forever be Red Sox World Series champions."
Betts' arrival is huge for the Dodgers, who won their last World Series title in 1988.
He hit 29 home runs and 80 RBIs while batting .295 last year, while scoring a career-high 135 runs.
Left-handed pitcher Price, 34, is a five-time All-Star, although the last of those came in 2015.