Sunderland have bolstered their attack by signing striker Ross Stewart from Ross County for an undisclosed fee.
Stewart scored 11 times in the Scottish Premiership last season and has agreed an initial two-and-a-half-year deal at the Stadium of Light.
"Ross is a player that will be great for us in the short term, but he can also develop and improve over the long term," said head coach Lee Johnson.
"He's at a good age, he's very fit and quick, and he obviously has good height as well, so he has all attributes to succeed."
Johnson has also brought in midfielder Carl Winchester, full-back Jake Vokins and forward Jordan Jones in January.