It wasnarrated from Abu Hurairah that the Prophet (ﷺ) said:
"Whoevercatches one Rak'ah of Friday, let him add another Rak'ah toit." (PT)
English reference (PT): Vol. 1, Book 5, Hadith 1121 (PT)
Arabic reference (PT): Book 5, Hadith 1175 (PT)