She's recently been linked to "Heroes" co-star Milo Ventimiglia -- but Hayden Panettiere was spotted partying with singer/songwriter Ne-Yo last night in NYC.

Hayden and Ne-Yo were caught leaving Butter together, and even ended up going back to the same hotel. Coincidence?

The pairing isn't completely random though -- the two have been working together to promote World Children's Day to support Ronald McDonald House Charities.