In a rare showdown between two 1500m world champions, Team Kenya and Team Ethiopia are putting together stacked quartets to headline the mixed relay competition at the IAAF World Cross Country Championships this Sunday in Kampala, Uganda.

The Kenyan team boasts three-time 1500m world champion and Olympic gold medalist Asbel Kiprop, who is returning from a season in which he finished sixth at the Olympic Games. Team Ethiopia will run women's 1500m world record-holder and world champion Genzebe Dibaba, who earned an Olympic silver medal in Rio last summer. The mixed relay consists of two men and two women who will each run a 2K loop, in any order they choose.

Along with their hardware earned on the track, both Kiprop and Dibaba have extensive cross country experience on their resumes. When Kiprop was 17, he won the U20 race at the IAAF World Cross Country Championships. In the same championship, Dibaba finished fifth in the women's race. She later earned U20 titles at the 2008 and 2009 IAAF World Cross Country Championships.

Team Kenya will also include Bernard Kipkorir Koros, Winfred Nzisa Mbithe, and Beatrice Chepkoech. Mbithe was fourth in the 1500m at the 2016 IAAF World Junior Championships. Chepkoech will provide a strong anchor leg after earning a fourth-place finish in the steeplechase at the 2016 Olympic Games.

Team Ethiopia will pull from the strength of 3K world indoor champion Yomif Kejelcha. At just 19 years old, Kejelcha has already notched a world junior record of 7:28 in the 3K, a world championship title, and a fourth-place finish in the 5K at the 2015 world championships. World youth finalist Welde Tufa and Bone Cheluka will complete the team.

Team USA will also have an Olympic medalist on the roster as Paul Chelimo leads the team of Eleanor Fulton, Cory Leslie, and Marisa Howard. With a stunning kick, Chelimo earned silver in the 5K with a personal best of 13:03 last summer. Fulton is returning from a seventh-place finish in the 1K at the USATF Indoor Championships. Leslie most recently finished ninth in the Wannamaker Mile at the Millrose Games, and Howard notched a 16th-place finish at the USATF Cross Country Championships in February.

The mixed relay will be the first of five races at the IAAF World Cross Country Championships.