All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Assuming Ihraam, according to the Muslim jurists is the intention to carry out the rituals, and it has no connection with wearing the lower and upper garments which form the garment of Ihraam. Also, these garments are not exclusive to Ihraam. In other words, whoever assumes Ihraam and does not wear the garment of Ihraam, his Ihraam will be correct but he will be required to take off his form-fitting clothes immediately. The Muslim who puts on the garment of Ihraam will not be considered in the state of Ihraam unless he intends to carry out the rituals. There is no difference between scholars on this.
Allaah Knows best.