Tragic news today, David Cook announced this weekend,  he has lost his brother Adam to brain cancer. You may have remembered his brother Adam, who was seen in the audience cheering David  on during the competition.

After battling cancer for more than 10 years, American Idol star David Cook’s brother, Adam, 37, succumbed to the disease Saturday. David made the announcement at the Washington D.C. Race for Hope 5K, which raises money to support finding a cure for brain cancer, this morning. “Like everybody here, I’m affected by this disease. I actually lost my brother yesterday to a brain tumor,” Cook said, as you can hear members of the crowd gasping. “I couldn’t imagine… I couldn’t imagine being anywhere else right now.” David was serving as grand marshal of the event and ran the 3.1 miles in 28 minutes. “I lost one today,” Cook added. “But I’ve gained 9,000 and I will be here every year that they will have me.”

In honor of Adam’s memory, fans can make donations to David’s Race for Hope team, the singer’s rep tells EW. (Contributions will be accepted through Sept. 30.) So far, the team has raised more than $51,000.

Our thoughts and prayers go out to his David’s family.