Country legend Willie Nelson has been forced to postpone back-to-back shows this week due to an unspecified illness. A statement on his website only explained Thursday night’s postponement in Washington D.C., saying, “The show tonight at 9:30 Club has been postponed due to illness. All tickets will be honored for the new date once it is rescheduled. Check back soon for more details.”

Friday night’s show at the Akron Civic Center in Akron, Ohio has also been postponed, according to a press release. No make up dates for either show have been announced. The Akron show was the second try at this Nelson concert. Originally, that show was scheduled for Oct. 18.

Nelson was forced to cancel concerts earlier this year as well. In April, he took ill and had to rearrange his schedule to honor all concert commitments. The 78-year-old has not suffered any major illnesses lately, so there’s no reason to believe he’s suffering from anything more than a seasonal flu or cold.

Nelson has seven dates remaining on his 2011 schedule and a heavy load for January and early February. Recently, Nelson announced he’d release an album of classic country covers on Nov. 21.