8:55 AM PT -- Sources close to the situation tell TMZ ... Tristan showed up alone to the restaurant and he exchanged hugs with Kim when he saw her. We're told the embrace was cordial ... Tristan actually sat down with her crew and hung around for a bit.
Our sources say even though Khloe's not with Tristan, they consider him family because he's Khloe's baby daddy. We're told cameras were rolling for 'KUWTK.'
Kim Kardashian hit up one of the more than 30,000 restaurants in NYC ... and somehow her sister's ex, Tristan Thompson, ended up there too.