diff --git a/src/lexer.rs b/src/lexer.rs
index bfaf55c4d2..322648f22c 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -832,11 +832,6 @@ impl<'src> Lexer<'src> {
   /// Cooked string: "[^"]*" # also processes escape sequences
   /// Raw string:    '[^']*'
   fn lex_string(&mut self, format_string_kind: Option<StringKind>) -> CompileResult<'src> {
-    let format = format_string_kind.is_some()
-      || self.tokens.last().is_some_and(|token| {
-        token.kind == TokenKind::Identifier && token.lexeme() == Keyword::F.lexeme()
-      });
-
     let kind = if let Some(kind) = format_string_kind {
       self.presume_str(Self::INTERPOLATION_END)?;
       kind
@@ -849,6 +844,12 @@ impl<'src> Lexer<'src> {
       kind
     };
 
+    let format = format_string_kind.is_some()
+      || kind.delimiter != StringDelimiter::Backtick
+        && self.tokens.last().is_some_and(|token| {
+          token.kind == TokenKind::Identifier && token.lexeme() == Keyword::F.lexeme()
+        });
+
     let mut escape = false;
 
     loop {
diff --git a/tests/format_string.rs b/tests/format_string.rs
index 1ba51b16c9..2d9c0e9b7b 100644
--- a/tests/format_string.rs
+++ b/tests/format_string.rs
@@ -327,3 +327,19 @@ fn mismatched_closing_delimiter_in_format_string() {
     )
     .failure();
 }
+
+#[test]
+fn format_backticks_are_forbidden() {
+  Test::new()
+    .justfile("foo := f`echo {{ arch() }}`")
+    .stderr(
+      "
+        error: expected '&&', '!=', '!~', '||', comment, end of file, end of line, '==', '=~', '(', '+', '++', or '/', but found backtick
+         ——▶ justfile:1:9
+          │
+        1 │ foo := f`echo {{ arch() }}`
+          │         ^^^^^^^^^^^^^^^^^^^
+      ",
+    )
+    .failure();
+}