Mosab Hassan Yousef, a former Israeli agent and the son of a West Bank Hamas leader, landed at Ben-Gurion Airport in Israel on Wednesday evening.
He was held up at passport control for several hours before being permitted to enter the country.
Yousef, known as the "Green Prince", is considered to have been one of Israel's best undercover agents close to Hamas leadership during the Second Intifada. His story was first exposed by Haaretz.
In recent years, he has lived in the U.S., where he received political asylum. After the publication of his book "Son of Hamas" he has given lectures to many audiences, including Jewish groups.
Recently, Yousef was in contact with Israeli parliamentarians who invited him to visit the Knesset.
Yousef arrived in Israel with a written invitation from Deputy Minister Ayoub Kara (Likud).
A few months ago, Yousef met with Deputy Foreign Minister Danny Ayalon (Yisrael Beiteinu) in Germany. MK Einat Wilf was also involved in the talks to bring him to Israel.
Yousef's father is imprisoned in Israel and is boycotting his son.
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