He may have only played for Watford four times but Britt Assombalonga has earned the club more than £3.3m following his transfer to Nottingham Forest tonight.

The 21-year-old made two starts and two substitute appearances for the Golden Boys in 2012 but struggled to make an impact in the Championship.

The striker impressed on loan at League Two side Southend United during the 2012/13 campaign and this prompted Peterborough United to break their club transfer record to sign him last summer.

Peterborough reportedly paid £1.2m for Assombalonga and we understand Watford agreed a 50 per cent sell-on fee on any profit made by Posh should they sell the player.

Nottingham Forest have tonight completed the signing of Assombalonga for a reported £5.5m, which, if correct, means the Hornets would now be due an additional £2.15m from Peterborough.

Assombalonga scored 33 goals in 58 games for Peterborough in all competitions last season but he did not join a professional club until he was 17.

At the age of 16, the striker decided to enrol at Hertswood School where he considered doing, among other subjects, law. It wasn't until he arrived that he learned about a scheme with Watford's community trust, which combined education and playing football.

Assombalonga, who played out wide as well as up top for the Hornets academy, progressed through the various trials to secure a spot on the team and his performances led to a recommendation to Watford, who offered him a trial.

After being given a scholarship with the club, he impressed for the Under-18s and Reserves and was handed a professional contract by the Hornets in 2011.

He scored 11 goals in 15 appearances at then Ryman Premier side Wealdstone during the 2011/12 season before netting five goals in as many games at Braintree Town in the Conference.

This prompted Sean Dyche to recall the player and hand him his Watford debut. He was given a contract extension by Watford in January 2013, whilst he was impressing on loan at Southend.

Assombalonga was born in the Democratic Republic of Congo, then called Zaire, but moved to England when he was eight months old and grew up in north London.

Tonight Assombalonga tweeted: "Happy to have signed for #NFFC [Nottingham Forest], want to say thank you to everyone at #PUFC [Peterborough] for everything they done for me. Was real good there! God bless."