diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d6a77d..48b9b4a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # v0.0.1
 
 MVP nodes:
+- `Add String to Format-Dict`
 - `Format-Dict from Text`
 - `Format-Dict Preview`
 - `String Formatter`
diff --git a/__init__.py b/__init__.py
index df80d2b..83000be 100644
--- a/__init__.py
+++ b/__init__.py
@@ -4,16 +4,19 @@
 
 import typing as _t
 
+from .node_dict_add_string import StringConstructorDictAddString
 from .node_dict_from_text import StringConstructorDictFromText
 from .node_dict_preview import StringConstructorDictPreview
 from .node_formatter import StringConstructorFormatter
 
 NODE_CLASS_MAPPINGS: _t.Dict[str, type] = {
+	'StringConstructorDictAddString': StringConstructorDictAddString,
 	'StringConstructorDictFromText': StringConstructorDictFromText,
 	'StringConstructorDictPreview': StringConstructorDictPreview,
 	'StringConstructorFormatter': StringConstructorFormatter,
 }
 NODE_DISPLAY_NAME_MAPPINGS: _t.Dict[str, str] = {
+	'StringConstructorDictAddString': "Add String to Format-Dict",
 	'StringConstructorDictFromText': "Format-Dict from Text",
 	'StringConstructorDictPreview': "Preview Format-Dict",
 	'StringConstructorFormatter': "String Formatter",
diff --git a/funcs_dict_add_string.py b/funcs_dict_add_string.py
new file mode 100644
index 0000000..da61249
--- /dev/null
+++ b/funcs_dict_add_string.py
@@ -0,0 +1,29 @@
+# encoding: utf-8
+"""
+The actual code (MVC pattern) for `StringConstructorDictString` node.
+"""
+
+import typing as _t
+
+from frozendict import deepfreeze as _deepfreeze
+
+from .enums import T as _T
+from .funcs_common import _raise_from_errors_dict, _validate_key, _verify_input_dict
+
+def set_dict_string(
+	name: str, value: str, strip_lines=True, in_dict: _t.Dict[str, _T] = None,
+	# unique_id: str = None,
+):
+	"""Update/append a string to the dict."""
+	out_dict: _t.Dict[str, _T] = _verify_input_dict(in_dict)
+	errors_dict: _t.Dict[_t.Any, str] = dict()
+	name = _validate_key(name, errors_dict)
+	_raise_from_errors_dict(errors_dict)
+	value = str(value)
+	if strip_lines:
+		value = '\n'.join(
+			x.strip() for x in value.splitlines()
+		)
+	new_dict: _t.Dict[str, str] = {name: value}
+	out_dict.update(new_dict)
+	return (_deepfreeze(out_dict),)
diff --git a/node_dict_add_string.py b/node_dict_add_string.py
new file mode 100644
index 0000000..189c7ff
--- /dev/null
+++ b/node_dict_add_string.py
@@ -0,0 +1,65 @@
+# encoding: utf-8
+"""
+"""
+
+import typing as _t
+
+from inspect import cleandoc as _cleandoc
+
+from frozendict import deepfreeze as _deepfreeze
+
+from comfy.comfy_types.node_typing import IO as _IO
+
+from . import _meta
+from .docstring_formatter import format_docstring as _format_docstring
+from .enums import DataTypes as _DataTypes
+from .funcs_dict_add_string import set_dict_string as _set_dict_string
+
+
+# A tiny optimization by reusing the same immutable dict:
+_input_types = _deepfreeze({
+	'required': {
+		'name': (_IO.STRING, {'tooltip': (
+			"Name of the substring inserted into the dict. "
+			"It must comprise only of latin letters, digits and underscores + it can't start with a digit."
+		)}),
+		'cleanup': (_IO.BOOLEAN, {'default': True, 'label_on': 'extra spaces', 'label_off': 'no', 'tooltip': (
+			"When enabled, each line in the sub-string is stripped from any spaces at its start and end."
+		)}),
+		'string': (_IO.STRING, {'multiline': True, 'tooltip': "The actual sub-string to set into the dict."}),
+	},
+	'optional': {
+		'str_dict': _DataTypes.input_str_dict(tooltip=(
+			"The dictionary to take named sub-strings from. It could be left unconnected, if the pattern doesn't reference "
+			"any sub-strings - then, this node acts exactly the same as a regular string-primitive node."
+		)),
+	},
+	# 'hidden': {
+	# 	'unique_id': 'UNIQUE_ID',  # used for text display at the bottom of the node
+	# },
+})
+
+
+class StringConstructorDictAddString:
+	"""Add/update a string to the Format-Dict."""
+	NODE_NAME = 'StringConstructorDictAddString'
+	CATEGORY = _meta.category
+	DESCRIPTION = _format_docstring(_cleandoc(__doc__))
+
+	OUTPUT_NODE = True  # Just to show the status message even if not connected to anything
+
+	FUNCTION = 'main'
+	RETURN_TYPES = (_DataTypes.STR_DICT, )
+	RETURN_NAMES = (_DataTypes.STR_DICT.lower(), )
+	# OUTPUT_TOOLTIPS = tuple()
+
+	@classmethod
+	def INPUT_TYPES(cls):
+		return _input_types
+
+	def main(
+		self, name: str, cleanup: bool, string: str,
+		str_dict: _t.Dict[str, _t.Any] = None,
+		# unique_id: str = None,
+	):
+		return _set_dict_string(name, string, strip_lines=cleanup, in_dict=str_dict)