if prefix, suffix, ok := splitUSTARPath(hdr.Name); ok {
		namePrefix, hdr.Name = prefix, suffix
	}

	// Pack the main header.
	var f formatter
	blk := tw.templateV7Plus(hdr, f.formatString, f.formatOctal)
	f.formatString(blk.toUSTAR().prefix(), namePrefix)
	blk.setFormat(FormatUSTAR)
	if f.err != nil {
		return f.err // Should never happen since header is validated
	}