Reference: Fataawa wa Rasaa.il Shaykh ‘Abdur-Razzaaq ‘Afeefee – Page 404, Fatwa No.7
Question: Should he pray the Tahiyyatul-Masjid (2 rak’ah prayer) when he enters the masjid whilst the adhaan for Jumu’ah is being called?
Response: Yes. If a Muslim enters the masjid whilst the adhaan for Jumu’ah is being called, then he should pray the Tahiyyatul-Masjid and not wait until the mu.adhdhin has finished [calling the adhaan].