This happened when I was still pretty new to the Christian faith, before I was baptised. Back then I was in a relationship with my ex-girlfriend (an Anglican). Her late grandaunt (a Catholic) passed away and she brought me to attend her funeral Mass.
So basically she, an Anglican/protestant, received the Eucharist. She told me that I shouldn’t receive the Eucharist unless “I have let Jesus in my heart”. I told her I did, and she was like “oh okay, then you can have it”. And so I received the Eucharist, not knowing that it’s actually the real body and blood of Jesus Christ.
We eventually broke up, and I eventually got baptised in an evangelical/non-denominational church, and am now about to