Alice Harrison was travelling on the Northern line with friends Anna Lambert, Emma Thornton and Victoria Janes when they spotted the former Labour leader.
The group, all 19, had boarded the train at Euston at about 8pm on Friday and were ‘subtly’ posing for selfies with Mr Miliband in the background when he approached them.
Ms Harrison tweeted the pictures, saying: "When @Ed_Miliband asks for a photo because he catches you taking a selfie on the tube."
She told the Standard: “He was already there [when we got on the Tube].
“I didn't spot him but my friend did and we were trying to be subtle, and my friend was taking selfies trying to get him in it and he posed for them.
“He then got up and the lady next to him was like "do you want me to take a photo of you" and Ed was like 'you guys are being very obvious'."
“He was really lovely. He was talking to us for a bit and laughing at us.”
Mr Miliband even took the chance to crack a joke about Ed Sheeran.
Ms Harrison added: “Everyone on the Tube was laughing and taking photos of us, and my friend said something about Ed Sheeran and he was like ‘I’m not Ed Sheeran by the way’ and laughed.”
Matt Spencer captured the scenes on video, tweeting: “Can confirm the #Milifandom is well and truly still active.
“@Ed_Miliband being a class act on the @northernline right now.”
Last year a Tube traveller captured on camera the moment he was stared out by Ed Miliband - and his photo of the glaring ex-Labour leader also went viral.