<human>:  Has Justin Timberlake ever written a song about Britney Spears?
<bot>: Yes, Justin Timberlake has written a song about Britney Spears. Justin Timberlake and Britney Spears dated in 1999. In 2002, Justin Timberlake released a music video for his breakup song 'Cry Me A River' and featured an actress who resembled his then ex Britney Spears. So Justin Timberlake has written a song about Britney Spears, yes he has.