Yes, you can control the Philips Hue Solo Lightstrip and define colours without additional accessories, but with some restrictions.

- You can control the Lightstrip with Bluetooth, which allows you to change the colour, brightness and intensity directly via the Philips Hue app without the need for a Hue Bridge.
- You can also control the Lightstrip with smart home assistants such as Amazon Alexa, Google Assistant and Apple HomeKit.

However, for full functionality, including automations and remote control, a Hue Bridge is required, which must be purchased separately.