Cambridge confirmed Ikpeazu had rejected a new contract with the League Two side and had informed the club of his decision to sign a pre-contract agreement elsewhere.
HITC Sport can reveal that Hearts is the mystery club Ikpeazu has agreed to join next season when his contract at Cambridge expires.
The 23-year-old has decided to reject the offer of a new deal at Cambridge and join Hearts as he expressed a desire to play at a higher level.
Ikpeazu joined Cambridge from Watford in the summer of 2016 and has scored 22 goals in 78 appearances for the club.
The former Reading youngster has scored 14 times so far this season for Cambridge and is the club's top scorer this term.
Hearts boss Craig Levein is busy planning for next season and sees Ikpeazu as a key addition to his plans, as he will add pace and goals to his attacking options at Tynecastle.