From Sahih Muslim (Hadith 3516):
Nafil reported:I heard Abdullah b. Umar (Allah be pleased with them) narrating that Allah's Messenger (ﷺ) said: Accept the feast when you are invited to it. And Abdullah (b. Umar) used to come to the feast, whether it was a wedding feast or other than that, and he would come there even in the state of fasting
Reference: Muslim 3516