Gaga, 26, wore a typical green hat and teamed it with a leopard print silk scarf and large green earrings.
"Safari Picture: In this photo I'm about 10 feet from 13 lions, 2 cubs. I spent about 30 minutes with them and took a nap! The lion pride even woke up at one point and let us come closer (sic)," she posted on Twitter.
The 'Poker Face' hitmaker was in Johannesburg for her world tour.
"Johannesburg was so wonderful, I can't really put it into words. I'm so happy, I haven't slept yet. Laying in bed dreaming of the next tour," she posted about her performance at the FNB Stadium.