Yes it would be illegal because:
In al-Saheehayn it is narrated that ‘Abd-Allaah ibn Mas’ood (may Allaah be pleased with him) said: “May Allaah curse the women who do tattoos and those for whom tattoos are done, those who pluck their eyebrows and those who file their teeth for the purpose of beautification and alter the creation of Allaah.” (al-Bukhaari, al-Libaas, 5587; Muslim, al-Libaas, 5538).
and why would you believe and follow this statement of the Prophet? because of the following Ayaahs of the Quran.
**He who obeys the Messenger has indeed obeyed . [An-Nisaa 4:80] **
In the Messenger of Allah is a good example for you to follow. [Al-Ahzab 33:21]