The forward joins Jack Ross' squad after the club finally added an attacker on deadline day.
Sterling is something of an unknown quantity, but what do we know about the new signing?
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What is his background?
Sterling grew up in Enfield and was part of Leyton Orient's youth programme as a youngster. However, he joined Spurs on July 1, 2015.
He has represented England at Under-17 and Under-18 level.
Has he played much for Spurs?
In a word, no. Sterling has just 11 minutes of senior football under his belt. He made his first-team debut in the Champions League back in December 2017, coming on as an 88th-minute substitute against Apoel Nicosia.
He was drafted in as a late replacement for fellow striker Fernando Llorente to sit on the bench in the Premier League for the first time in a 3-1 home defeat by Manchester City in April, 2018, but didn't get on.
Sterling finally made another appearance for the first team, coming on with nine minutes left of Spurs' 2-0 FA Cup defeat against Crystal Palace earlier this month.
What about his youth career?
Sterling has been a prolific scorer with the youth teams at Spurs. He was the club's top scorer in Premier League 2 last season with eight goals in his 20 appearances.
He has also scored against Sunderland in the past, netting the winner for the U23s in February 2017, robbing goalkeeper Max Stryjek at the edge of his own area and firing home
Sterling scored three goals in six starts in the Under-19 UEFA Youth League too as Spurs reached the quarter-final stage.
He has been in decent form this season too, and scored twice as Spurs beat 10-man Manchester City in Premier League 2 in December.
Interestingly, Sterling did score for Tottenham's Under-21s in the Football League Trophy last season when they lost 4-3 against AFC Wimbledon...who just happen to be Sunderland's opponents on Saturday.
What are his attributes?
The youngster is raw, having just turned 20 in November, and at 5ft 9in he won't be expected to provide a physical presence up front. However, Ross could look to use him as an impact player, utilising his pace and eye for goal from the bench initially.
Ross said: “He’s athletic, good on the ball and has an eye for goal, so he has all the attributes at his disposal to ensure he’s a success during his time at the Stadium of Light.”