Matthew Hocter from Albumism described "We Didn't Know" as a "gentle
ballad".
J.D. Considine from
The Baltimore Sun wrote that it, "in which Houston merely follows the lead of duet partner
Stevie Wonder, also has its pleasures, most of which stem from Wonder's deliciously idiosyncratic writing."
David Browne from
Entertainment Weekly called the song "sluggish". He added that this contribution "blends into the mush".
People Magazine stated that "if Houston thought she could shut critics up by recording a tartly appealing Stevie Wonder song about friendship turning into love, 'We Didn't Know'—and recording it as a touching duet with Wonder himself—she was right". James Hunter from
Rolling Stone adored the song and praised it with a long review, "Still, the key to the kind of music Houston sings on ''
I'm Your Baby Tonight''—the black-and-white,
funk-and-
dance-driven
pop that is the soundtrack of this cultural moment—is 'We Didn't Know'." He noted further, "Wonder, who practically invented the keyboard-based pop that Houston and her fans hear as natural and contemporary, understands Houston totally. He knows what she likes about the expressive properties of ballads, about the passion of
rock, about the well-regulated technological zing of dance music. So, as he's done before in his own music and with other singers, he puts all of this—the barreling rhythm tracks, the soaring choruses, the personable background voices—at the service of 'We Didn't Know', which is about when 'innocent friends/Turn serious lovers.' Chances are—and with any luck—this emotionally engaged song on Whitney Houston's consistent and resourceful album will affect the music she sings for the rest of her life." ==Chart performance==