diff --git a/src/parser/validate.ts b/src/parser/validate.ts
index 82c80af22..e0fccb6bf 100644
--- a/src/parser/validate.ts
+++ b/src/parser/validate.ts
@@ -49,8 +49,8 @@ export function validate(parse: {
     if (intersection.length === 0) {
       // the command's exactlyOne may or may not include itself, so we'll use Set to add + de-dupe
       throw new CLIError(`Exactly one of the following must be provided: ${[
-        ...new Set(...flag.exactlyOne || [], flag.name),
-      ].join(',')}`)
+        ...new Set(flag.exactlyOne?.map(flag => `--${flag}`)),
+      ].join(', ')}`)
     }
   }
 
diff --git a/test/parser/parse.test.ts b/test/parser/parse.test.ts
index 5bea4f4cc..590213924 100644
--- a/test/parser/parse.test.ts
+++ b/test/parser/parse.test.ts
@@ -812,15 +812,15 @@ See more help with --help`)
       try {
         await parse([], {
           flags: {
-            foo: flags.string({exactlyOne: ['bar']}),
-            bar: flags.string({char: 'b', exactlyOne: ['foo']}),
+            foo: flags.string({exactlyOne: ['bar', 'foo']}),
+            bar: flags.string({char: 'b', exactlyOne: ['bar', 'foo']}),
           },
         })
       } catch (error: any) {
         message = error.message
       }
 
-      expect(message).to.equal('Exactly one of the following must be provided: b,a,r')
+      expect(message).to.equal('Exactly one of the following must be provided: --bar, --foo')
     })
 
     it('throws if multiple are set', async () => {