From Sahih Bukhari (Hadith 1781):
Narrated Abu 'Is-haq:I asked Masruq, `Ata' and Mujahid (about the `Umra of Allah's Messenger (ﷺ)). They said, "Allah's Messenger (ﷺ) had performed `Umra in Dhi-l-Qa'da before he performed Hajj." I heard Al-Bara' bin `Azib saying, "Allah's Messenger (ﷺ) had performed `Umra in Dhi-l-Qa'da twice before he performed Hajj
Reference: Bukhari 1781