diff --git a/pkg/textparse/lex.l b/pkg/textparse/lex.l
index 3decbb1ca..4a0b45e10 100644
--- a/pkg/textparse/lex.l
+++ b/pkg/textparse/lex.l
@@ -46,6 +46,7 @@ func (l *lexer) Lex() int {
 %}
 
 D     [0-9]
+S     [a-zA-Z]
 L     [a-zA-Z_]
 M     [a-zA-Z_:]
 
@@ -63,9 +64,9 @@ M     [a-zA-Z_:]
 #[^\r\n]*\n                           l.mstart = l.i
 [\r\n \t]+                            l.mstart = l.i
 
-{L}({L}|{D})*\{                       s = lstateLabels
+{S}({M}|{D})*\{                       s = lstateLabels
                                       l.offsets = append(l.offsets, l.i-1)
-{L}({L}|{D})*                         s = lstateValue
+{S}({M}|{D})*                         s = lstateValue
                                       l.mend = l.i
                                       l.offsets = append(l.offsets, l.i)
 
@@ -75,7 +76,7 @@ M     [a-zA-Z_:]
 <lstateLabels>,?                      s = lstateLName
                                       l.offsets = append(l.offsets, l.i)
 
-<lstateLName>{M}({M}|{D})*=           s = lstateLValue
+<lstateLName>{S}({L}|{D})*=           s = lstateLValue
                                       l.offsets = append(l.offsets, l.i-1)
 
 <lstateLValue>\"(\\.|[^\\"])*\"       s = lstateLabels
diff --git a/pkg/textparse/lex.l.go b/pkg/textparse/lex.l.go
index 11ebde484..9b9e731b0 100644
--- a/pkg/textparse/lex.l.go
+++ b/pkg/textparse/lex.l.go
@@ -77,7 +77,7 @@ yystart1:
 		goto yystate3
 	case c == '\x00':
 		goto yystate2
-	case c >= 'A' && c <= 'Z' || c == '_' || c >= 'a' && c <= 'z':
+	case c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z':
 		goto yystate6
 	}
 
@@ -116,7 +116,7 @@ yystate6:
 		goto yyrule5
 	case c == '{':
 		goto yystate7
-	case c >= '0' && c <= '9' || c >= 'A' && c <= 'Z' || c == '_' || c >= 'a' && c <= 'z':
+	case c >= '0' && c <= ':' || c >= 'A' && c <= 'Z' || c == '_' || c >= 'a' && c <= 'z':
 		goto yystate6
 	}
 
@@ -275,7 +275,7 @@ yystart23:
 	switch {
 	default:
 		goto yyabort
-	case c == ':' || c >= 'A' && c <= 'Z' || c == '_' || c >= 'a' && c <= 'z':
+	case c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z':
 		goto yystate24
 	}
 
@@ -286,7 +286,7 @@ yystate24:
 		goto yyabort
 	case c == '=':
 		goto yystate25
-	case c >= '0' && c <= ':' || c >= 'A' && c <= 'Z' || c == '_' || c >= 'a' && c <= 'z':
+	case c >= '0' && c <= '9' || c >= 'A' && c <= 'Z' || c == '_' || c >= 'a' && c <= 'z':
 		goto yystate24
 	}
 
@@ -373,13 +373,13 @@ yyrule3: // [\r\n \t]+
 		l.mstart = l.i
 		goto yystate0
 	}
-yyrule4: // {L}({L}|{D})*\{
+yyrule4: // {S}({M}|{D})*\{
 	{
 		s = lstateLabels
 		l.offsets = append(l.offsets, l.i-1)
 		goto yystate0
 	}
-yyrule5: // {L}({L}|{D})*
+yyrule5: // {S}({M}|{D})*
 	{
 		s = lstateValue
 		l.mend = l.i
@@ -401,7 +401,7 @@ yyrule8: // ,?
 		l.offsets = append(l.offsets, l.i)
 		goto yystate0
 	}
-yyrule9: // {M}({M}|{D})*=
+yyrule9: // {S}({L}|{D})*=
 	{
 		s = lstateLValue
 		l.offsets = append(l.offsets, l.i-1)
diff --git a/pkg/textparse/parse_test.go b/pkg/textparse/parse_test.go
index bfb91aa30..d1afa8c50 100644
--- a/pkg/textparse/parse_test.go
+++ b/pkg/textparse/parse_test.go
@@ -34,6 +34,7 @@ go_gc_duration_seconds{quantile="0"} 4.9351e-05
 go_gc_duration_seconds{quantile="0.25"} 7.424100000000001e-05
 go_gc_duration_seconds{quantile="0.5",a="b"} 8.3835e-05
 go_gc_duration_seconds_count 99
+some:aggregate:rate5m{a_b="c"}	1
 # HELP go_goroutines Number of goroutines that currently exist.
 # TYPE go_goroutines gauge
 go_goroutines 33  	123123`
@@ -62,6 +63,10 @@ go_goroutines 33  	123123`
 			m:    `go_gc_duration_seconds_count`,
 			v:    99,
 			lset: labels.FromStrings("__name__", "go_gc_duration_seconds_count"),
+		}, {
+			m:    `some:aggregate:rate5m{a_b="c"}`,
+			v:    1,
+			lset: labels.FromStrings("__name__", "some:aggregate:rate5m", "a_b", "c"),
 		}, {
 			m:    `go_goroutines`,
 			v:    33,